* possible deadlock in sidtab_sid2str_put @ 2020-01-28 4:27 syzbot 2020-01-28 12:50 ` syzbot 2020-01-28 15:28 ` syzbot 0 siblings, 2 replies; 11+ messages in thread From: syzbot @ 2020-01-28 4:27 UTC (permalink / raw) To: eparis, jeffv, keescook, linux-kernel, omosnace, paul, paulmck, sds, selinux, syzkaller-bugs Hello, syzbot found the following crash on: HEAD commit: b0be0eff Merge tag 'x86-pti-2020-01-28' of git://git.kerne.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15232735e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=9784e57c96a92f20 dashboard link: https://syzkaller.appspot.com/bug?extid=61cba5033e2072d61806 compiler: gcc (GCC) 9.0.0 20181231 (experimental) Unfortunately, I don't have any reproducer for this crash yet. IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+61cba5033e2072d61806@syzkaller.appspotmail.com ===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected 5.5.0-syzkaller #0 Not tainted ----------------------------------------------------- syz-executor.3/20867 [HC0[0]:SC0[2]:HE1:SE0] is trying to acquire: ffff888022b68098 (&(&s->cache_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline] ffff888022b68098 (&(&s->cache_lock)->rlock){+.+.}, at: sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 and this task is already holding: ffffffff898605d8 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] ffffffff898605d8 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 which would create a new lock dependency: (&(&nf_conntrack_locks[i])->rlock){+.-.} -> (&(&s->cache_lock)->rlock){+.+.} but this new dependency connects a SOFTIRQ-irq-safe lock: (&(&nf_conntrack_locks[i])->rlock){+.-.} ... which became SOFTIRQ-irq-safe at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 nf_conntrack_double_lock.isra.0+0xac/0x100 net/netfilter/nf_conntrack_core.c:134 __nf_conntrack_confirm+0x252/0x1710 net/netfilter/nf_conntrack_core.c:963 nf_conntrack_confirm include/net/netfilter/nf_conntrack_core.h:63 [inline] nf_confirm+0x3e7/0x4d0 net/netfilter/nf_conntrack_proto.c:154 ipv4_confirm+0x14c/0x240 net/netfilter/nf_conntrack_proto.c:169 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline] nf_hook_slow+0xbc/0x1e0 net/netfilter/core.c:512 nf_hook include/linux/netfilter.h:262 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] ip_local_deliver+0x352/0x520 net/ipv4/ip_input.c:252 dst_input include/net/dst.h:442 [inline] ip_sublist_rcv_finish+0x9b/0x2d0 net/ipv4/ip_input.c:549 ip_list_rcv_finish net/ipv4/ip_input.c:599 [inline] ip_sublist_rcv+0x5a6/0xa20 net/ipv4/ip_input.c:607 ip_list_rcv+0x37e/0x4bf net/ipv4/ip_input.c:642 __netif_receive_skb_list_ptype net/core/dev.c:5193 [inline] __netif_receive_skb_list_core+0x5fc/0x9d0 net/core/dev.c:5241 __netif_receive_skb_list net/core/dev.c:5293 [inline] netif_receive_skb_list_internal+0x7eb/0xe50 net/core/dev.c:5388 gro_normal_list.part.0+0x1e/0xb0 net/core/dev.c:5499 gro_normal_list net/core/dev.c:6232 [inline] napi_complete_done+0x208/0x510 net/core/dev.c:6220 virtqueue_napi_complete+0x31/0xa0 drivers/net/virtio_net.c:329 virtnet_poll+0xbad/0xe90 drivers/net/virtio_net.c:1432 napi_poll net/core/dev.c:6534 [inline] net_rx_action+0x508/0x1120 net/core/dev.c:6602 __do_softirq+0x262/0x98c kernel/softirq.c:292 run_ksoftirqd kernel/softirq.c:603 [inline] run_ksoftirqd+0x8e/0x110 kernel/softirq.c:595 smpboot_thread_fn+0x6a3/0xa40 kernel/smpboot.c:165 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 to a SOFTIRQ-irq-unsafe lock: (&(&s->cache_lock)->rlock){+.+.} ... which became SOFTIRQ-irq-unsafe at: ... lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 sidtab_sid2str_put+0xa0/0xc0 security/selinux/ss/sidtab.c:566 sidtab_entry_to_string security/selinux/ss/services.c:1279 [inline] sidtab_entry_to_string+0xf2/0x110 security/selinux/ss/services.c:1266 security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 avc_audit_post_callback+0x102/0x790 security/selinux/avc.c:709 common_lsm_audit+0x5ac/0x1e00 security/lsm_audit.c:466 slow_avc_audit+0x16a/0x1f0 security/selinux/avc.c:782 avc_audit security/selinux/include/avc.h:140 [inline] avc_has_perm+0x543/0x610 security/selinux/avc.c:1185 inode_has_perm+0x1a8/0x230 security/selinux/hooks.c:1631 selinux_mmap_file+0x10a/0x1d0 security/selinux/hooks.c:3701 security_mmap_file+0xa4/0x1e0 security/security.c:1482 vm_mmap_pgoff+0xf0/0x230 mm/util.c:502 vm_mmap+0x94/0xc0 mm/util.c:525 elf_map+0x10a/0x2b0 fs/binfmt_elf.c:377 load_elf_binary+0xd4b/0x5310 fs/binfmt_elf.c:982 search_binary_handler fs/exec.c:1658 [inline] search_binary_handler+0x16d/0x570 fs/exec.c:1635 exec_binprm fs/exec.c:1701 [inline] __do_execve_file.isra.0+0x1329/0x22b0 fs/exec.c:1821 do_execveat_common fs/exec.c:1867 [inline] do_execve fs/exec.c:1884 [inline] __do_sys_execve fs/exec.c:1960 [inline] __se_sys_execve fs/exec.c:1955 [inline] __x64_sys_execve+0x8f/0xc0 fs/exec.c:1955 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&(&s->cache_lock)->rlock); local_irq_disable(); lock(&(&nf_conntrack_locks[i])->rlock); lock(&(&s->cache_lock)->rlock); <Interrupt> lock(&(&nf_conntrack_locks[i])->rlock); *** DEADLOCK *** 4 locks held by syz-executor.3/20867: #0: ffffffff8c1acc68 (&table[i].mutex){+.+.}, at: nfnl_lock net/netfilter/nfnetlink.c:62 [inline] #0: ffffffff8c1acc68 (&table[i].mutex){+.+.}, at: nfnetlink_rcv_msg+0x9ee/0xfb0 net/netfilter/nfnetlink.c:224 #1: ffff88800ce3c5d8 (nlk_cb_mutex-NETFILTER){+.+.}, at: netlink_dump+0xe7/0xfb0 net/netlink/af_netlink.c:2199 #2: ffffffff898605d8 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] #2: ffffffff898605d8 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 #3: ffffffff8b7df008 (&selinux_ss.policy_rwlock){.+.?}, at: security_sid_to_context_core+0x1ca/0x3c0 security/selinux/ss/services.c:1344 the dependencies between SOFTIRQ-irq-safe lock and the holding lock: -> (&(&nf_conntrack_locks[i])->rlock){+.-.} { HARDIRQ-ON-W at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 get_next_corpse net/netfilter/nf_conntrack_core.c:2001 [inline] nf_ct_iterate_cleanup+0x1d2/0x4e0 net/netfilter/nf_conntrack_core.c:2035 nf_ct_iterate_destroy+0x12e/0x160 net/netfilter/nf_conntrack_core.c:2162 nf_conntrack_helper_unregister+0x111/0x160 net/netfilter/nf_conntrack_helper.c:469 nf_conntrack_helpers_unregister net/netfilter/nf_conntrack_helper.c:532 [inline] nf_conntrack_helpers_register+0xaa/0xe0 net/netfilter/nf_conntrack_helper.c:523 nf_conntrack_sip_init+0x266/0x2a4 net/netfilter/nf_conntrack_sip.c:1693 do_one_initcall+0x120/0x820 init/main.c:939 do_initcall_level init/main.c:1007 [inline] do_initcalls init/main.c:1015 [inline] do_basic_setup init/main.c:1032 [inline] kernel_init_freeable+0x4ca/0x570 init/main.c:1203 kernel_init+0x12/0x1bf init/main.c:1110 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 IN-SOFTIRQ-W at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 nf_conntrack_double_lock.isra.0+0xac/0x100 net/netfilter/nf_conntrack_core.c:134 __nf_conntrack_confirm+0x252/0x1710 net/netfilter/nf_conntrack_core.c:963 nf_conntrack_confirm include/net/netfilter/nf_conntrack_core.h:63 [inline] nf_confirm+0x3e7/0x4d0 net/netfilter/nf_conntrack_proto.c:154 ipv4_confirm+0x14c/0x240 net/netfilter/nf_conntrack_proto.c:169 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline] nf_hook_slow+0xbc/0x1e0 net/netfilter/core.c:512 nf_hook include/linux/netfilter.h:262 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] ip_local_deliver+0x352/0x520 net/ipv4/ip_input.c:252 dst_input include/net/dst.h:442 [inline] ip_sublist_rcv_finish+0x9b/0x2d0 net/ipv4/ip_input.c:549 ip_list_rcv_finish net/ipv4/ip_input.c:599 [inline] ip_sublist_rcv+0x5a6/0xa20 net/ipv4/ip_input.c:607 ip_list_rcv+0x37e/0x4bf net/ipv4/ip_input.c:642 __netif_receive_skb_list_ptype net/core/dev.c:5193 [inline] __netif_receive_skb_list_core+0x5fc/0x9d0 net/core/dev.c:5241 __netif_receive_skb_list net/core/dev.c:5293 [inline] netif_receive_skb_list_internal+0x7eb/0xe50 net/core/dev.c:5388 gro_normal_list.part.0+0x1e/0xb0 net/core/dev.c:5499 gro_normal_list net/core/dev.c:6232 [inline] napi_complete_done+0x208/0x510 net/core/dev.c:6220 virtqueue_napi_complete+0x31/0xa0 drivers/net/virtio_net.c:329 virtnet_poll+0xbad/0xe90 drivers/net/virtio_net.c:1432 napi_poll net/core/dev.c:6534 [inline] net_rx_action+0x508/0x1120 net/core/dev.c:6602 __do_softirq+0x262/0x98c kernel/softirq.c:292 run_ksoftirqd kernel/softirq.c:603 [inline] run_ksoftirqd+0x8e/0x110 kernel/softirq.c:595 smpboot_thread_fn+0x6a3/0xa40 kernel/smpboot.c:165 kthread+0x361/0x430 kernel/kthread.c:255 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 INITIAL USE at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 get_next_corpse net/netfilter/nf_conntrack_core.c:2001 [inline] nf_ct_iterate_cleanup+0x1d2/0x4e0 net/netfilter/nf_conntrack_core.c:2035 nf_ct_iterate_destroy+0x12e/0x160 net/netfilter/nf_conntrack_core.c:2162 nf_conntrack_helper_unregister+0x111/0x160 net/netfilter/nf_conntrack_helper.c:469 nf_conntrack_helpers_unregister net/netfilter/nf_conntrack_helper.c:532 [inline] nf_conntrack_helpers_register+0xaa/0xe0 net/netfilter/nf_conntrack_helper.c:523 nf_conntrack_sip_init+0x266/0x2a4 net/netfilter/nf_conntrack_sip.c:1693 do_one_initcall+0x120/0x820 init/main.c:939 do_initcall_level init/main.c:1007 [inline] do_initcalls init/main.c:1015 [inline] do_basic_setup init/main.c:1032 [inline] kernel_init_freeable+0x4ca/0x570 init/main.c:1203 kernel_init+0x12/0x1bf init/main.c:1110 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 } ... key at: [<ffffffff8c1ad440>] __key.79496+0x0/0x40 ... acquired at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 sidtab_sid2str_put security/selinux/ss/sidtab.c:594 [inline] sidtab_sid2str_get+0x3b5/0x66e security/selinux/ss/sidtab.c:594 sidtab_entry_to_string+0x37/0x110 security/selinux/ss/services.c:1271 security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 selinux_secid_to_secctx+0x2d/0x40 security/selinux/hooks.c:6451 security_secid_to_secctx+0x75/0xc0 security/security.c:1950 ctnetlink_dump_secctx.isra.0+0x8c/0x330 net/netfilter/nf_conntrack_netlink.c:335 ctnetlink_dump_info net/netfilter/nf_conntrack_netlink.c:531 [inline] ctnetlink_fill_info+0x750/0xd40 net/netfilter/nf_conntrack_netlink.c:591 ctnetlink_dump_table+0x68c/0x1130 net/netfilter/nf_conntrack_netlink.c:979 netlink_dump+0x558/0xfb0 net/netlink/af_netlink.c:2244 __netlink_dump_start+0x66a/0x930 net/netlink/af_netlink.c:2352 netlink_dump_start include/linux/netlink.h:233 [inline] ctnetlink_get_conntrack+0x55e/0x6a0 net/netfilter/nf_conntrack_netlink.c:1355 nfnetlink_rcv_msg+0xcf2/0xfb0 net/netfilter/nfnetlink.c:229 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477 nfnetlink_rcv+0x1ba/0x460 net/netfilter/nfnetlink.c:563 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x58c/0x7d0 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:639 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:659 ____sys_sendmsg+0x753/0x880 net/socket.c:2330 ___sys_sendmsg+0x100/0x170 net/socket.c:2384 __sys_sendmsg+0x105/0x1d0 net/socket.c:2417 __do_sys_sendmsg net/socket.c:2426 [inline] __se_sys_sendmsg net/socket.c:2424 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2424 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe the dependencies between the lock to be acquired and SOFTIRQ-irq-unsafe lock: -> (&(&s->cache_lock)->rlock){+.+.} { HARDIRQ-ON-W at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 sidtab_sid2str_put+0xa0/0xc0 security/selinux/ss/sidtab.c:566 sidtab_entry_to_string security/selinux/ss/services.c:1279 [inline] sidtab_entry_to_string+0xf2/0x110 security/selinux/ss/services.c:1266 security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 avc_audit_post_callback+0x102/0x790 security/selinux/avc.c:709 common_lsm_audit+0x5ac/0x1e00 security/lsm_audit.c:466 slow_avc_audit+0x16a/0x1f0 security/selinux/avc.c:782 avc_audit security/selinux/include/avc.h:140 [inline] avc_has_perm+0x543/0x610 security/selinux/avc.c:1185 inode_has_perm+0x1a8/0x230 security/selinux/hooks.c:1631 selinux_mmap_file+0x10a/0x1d0 security/selinux/hooks.c:3701 security_mmap_file+0xa4/0x1e0 security/security.c:1482 vm_mmap_pgoff+0xf0/0x230 mm/util.c:502 vm_mmap+0x94/0xc0 mm/util.c:525 elf_map+0x10a/0x2b0 fs/binfmt_elf.c:377 load_elf_binary+0xd4b/0x5310 fs/binfmt_elf.c:982 search_binary_handler fs/exec.c:1658 [inline] search_binary_handler+0x16d/0x570 fs/exec.c:1635 exec_binprm fs/exec.c:1701 [inline] __do_execve_file.isra.0+0x1329/0x22b0 fs/exec.c:1821 do_execveat_common fs/exec.c:1867 [inline] do_execve fs/exec.c:1884 [inline] __do_sys_execve fs/exec.c:1960 [inline] __se_sys_execve fs/exec.c:1955 [inline] __x64_sys_execve+0x8f/0xc0 fs/exec.c:1955 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe SOFTIRQ-ON-W at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 sidtab_sid2str_put+0xa0/0xc0 security/selinux/ss/sidtab.c:566 sidtab_entry_to_string security/selinux/ss/services.c:1279 [inline] sidtab_entry_to_string+0xf2/0x110 security/selinux/ss/services.c:1266 security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 avc_audit_post_callback+0x102/0x790 security/selinux/avc.c:709 common_lsm_audit+0x5ac/0x1e00 security/lsm_audit.c:466 slow_avc_audit+0x16a/0x1f0 security/selinux/avc.c:782 avc_audit security/selinux/include/avc.h:140 [inline] avc_has_perm+0x543/0x610 security/selinux/avc.c:1185 inode_has_perm+0x1a8/0x230 security/selinux/hooks.c:1631 selinux_mmap_file+0x10a/0x1d0 security/selinux/hooks.c:3701 security_mmap_file+0xa4/0x1e0 security/security.c:1482 vm_mmap_pgoff+0xf0/0x230 mm/util.c:502 vm_mmap+0x94/0xc0 mm/util.c:525 elf_map+0x10a/0x2b0 fs/binfmt_elf.c:377 load_elf_binary+0xd4b/0x5310 fs/binfmt_elf.c:982 search_binary_handler fs/exec.c:1658 [inline] search_binary_handler+0x16d/0x570 fs/exec.c:1635 exec_binprm fs/exec.c:1701 [inline] __do_execve_file.isra.0+0x1329/0x22b0 fs/exec.c:1821 do_execveat_common fs/exec.c:1867 [inline] do_execve fs/exec.c:1884 [inline] __do_sys_execve fs/exec.c:1960 [inline] __se_sys_execve fs/exec.c:1955 [inline] __x64_sys_execve+0x8f/0xc0 fs/exec.c:1955 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe INITIAL USE at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 sidtab_sid2str_put+0xa0/0xc0 security/selinux/ss/sidtab.c:566 sidtab_entry_to_string security/selinux/ss/services.c:1279 [inline] sidtab_entry_to_string+0xf2/0x110 security/selinux/ss/services.c:1266 security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 avc_audit_post_callback+0x102/0x790 security/selinux/avc.c:709 common_lsm_audit+0x5ac/0x1e00 security/lsm_audit.c:466 slow_avc_audit+0x16a/0x1f0 security/selinux/avc.c:782 avc_audit security/selinux/include/avc.h:140 [inline] avc_has_perm+0x543/0x610 security/selinux/avc.c:1185 inode_has_perm+0x1a8/0x230 security/selinux/hooks.c:1631 selinux_mmap_file+0x10a/0x1d0 security/selinux/hooks.c:3701 security_mmap_file+0xa4/0x1e0 security/security.c:1482 vm_mmap_pgoff+0xf0/0x230 mm/util.c:502 vm_mmap+0x94/0xc0 mm/util.c:525 elf_map+0x10a/0x2b0 fs/binfmt_elf.c:377 load_elf_binary+0xd4b/0x5310 fs/binfmt_elf.c:982 search_binary_handler fs/exec.c:1658 [inline] search_binary_handler+0x16d/0x570 fs/exec.c:1635 exec_binprm fs/exec.c:1701 [inline] __do_execve_file.isra.0+0x1329/0x22b0 fs/exec.c:1821 do_execveat_common fs/exec.c:1867 [inline] do_execve fs/exec.c:1884 [inline] __do_sys_execve fs/exec.c:1960 [inline] __se_sys_execve fs/exec.c:1955 [inline] __x64_sys_execve+0x8f/0xc0 fs/exec.c:1955 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [<ffffffff8b7dec80>] __key.69173+0x0/0x40 ... acquired at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 sidtab_sid2str_put security/selinux/ss/sidtab.c:594 [inline] sidtab_sid2str_get+0x3b5/0x66e security/selinux/ss/sidtab.c:594 sidtab_entry_to_string+0x37/0x110 security/selinux/ss/services.c:1271 security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 selinux_secid_to_secctx+0x2d/0x40 security/selinux/hooks.c:6451 security_secid_to_secctx+0x75/0xc0 security/security.c:1950 ctnetlink_dump_secctx.isra.0+0x8c/0x330 net/netfilter/nf_conntrack_netlink.c:335 ctnetlink_dump_info net/netfilter/nf_conntrack_netlink.c:531 [inline] ctnetlink_fill_info+0x750/0xd40 net/netfilter/nf_conntrack_netlink.c:591 ctnetlink_dump_table+0x68c/0x1130 net/netfilter/nf_conntrack_netlink.c:979 netlink_dump+0x558/0xfb0 net/netlink/af_netlink.c:2244 __netlink_dump_start+0x66a/0x930 net/netlink/af_netlink.c:2352 netlink_dump_start include/linux/netlink.h:233 [inline] ctnetlink_get_conntrack+0x55e/0x6a0 net/netfilter/nf_conntrack_netlink.c:1355 nfnetlink_rcv_msg+0xcf2/0xfb0 net/netfilter/nfnetlink.c:229 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477 nfnetlink_rcv+0x1ba/0x460 net/netfilter/nfnetlink.c:563 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x58c/0x7d0 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:639 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:659 ____sys_sendmsg+0x753/0x880 net/socket.c:2330 ___sys_sendmsg+0x100/0x170 net/socket.c:2384 __sys_sendmsg+0x105/0x1d0 net/socket.c:2417 __do_sys_sendmsg net/socket.c:2426 [inline] __se_sys_sendmsg net/socket.c:2424 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2424 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe stack backtrace: CPU: 0 PID: 20867 Comm: syz-executor.3 Not tainted 5.5.0-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-prebuilt.qemu.org 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_bad_irq_dependency kernel/locking/lockdep.c:2094 [inline] check_irq_usage.cold+0x586/0x6fe kernel/locking/lockdep.c:2292 check_prev_add kernel/locking/lockdep.c:2479 [inline] check_prevs_add kernel/locking/lockdep.c:2580 [inline] validate_chain kernel/locking/lockdep.c:2970 [inline] __lock_acquire+0x25b4/0x4a00 kernel/locking/lockdep.c:3954 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 sidtab_sid2str_put security/selinux/ss/sidtab.c:594 [inline] sidtab_sid2str_get+0x3b5/0x66e security/selinux/ss/sidtab.c:594 sidtab_entry_to_string+0x37/0x110 security/selinux/ss/services.c:1271 security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 selinux_secid_to_secctx+0x2d/0x40 security/selinux/hooks.c:6451 security_secid_to_secctx+0x75/0xc0 security/security.c:1950 ctnetlink_dump_secctx.isra.0+0x8c/0x330 net/netfilter/nf_conntrack_netlink.c:335 ctnetlink_dump_info net/netfilter/nf_conntrack_netlink.c:531 [inline] ctnetlink_fill_info+0x750/0xd40 net/netfilter/nf_conntrack_netlink.c:591 ctnetlink_dump_table+0x68c/0x1130 net/netfilter/nf_conntrack_netlink.c:979 netlink_dump+0x558/0xfb0 net/netlink/af_netlink.c:2244 __netlink_dump_start+0x66a/0x930 net/netlink/af_netlink.c:2352 netlink_dump_start include/linux/netlink.h:233 [inline] ctnetlink_get_conntrack+0x55e/0x6a0 net/netfilter/nf_conntrack_netlink.c:1355 nfnetlink_rcv_msg+0xcf2/0xfb0 net/netfilter/nfnetlink.c:229 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477 nfnetlink_rcv+0x1ba/0x460 net/netfilter/nfnetlink.c:563 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x58c/0x7d0 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:639 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:659 ____sys_sendmsg+0x753/0x880 net/socket.c:2330 ___sys_sendmsg+0x100/0x170 net/socket.c:2384 __sys_sendmsg+0x105/0x1d0 net/socket.c:2417 __do_sys_sendmsg net/socket.c:2426 [inline] __se_sys_sendmsg net/socket.c:2424 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2424 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x45b3f9 Code: bd b1 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 8b b1 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007fbe326f8c88 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 000000000072bf00 RCX: 000000000045b3f9 RDX: 0000000000000000 RSI: 0000000020000500 RDI: 0000000000000003 RBP: 00007fbe326f96d4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000008f1 R14: 00000000004ba9a8 R15: 00000000006eaa80 --- This bug is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this bug report. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: possible deadlock in sidtab_sid2str_put 2020-01-28 4:27 possible deadlock in sidtab_sid2str_put syzbot @ 2020-01-28 12:50 ` syzbot 2020-01-28 13:39 ` Paul Moore 2020-01-28 15:28 ` syzbot 1 sibling, 1 reply; 11+ messages in thread From: syzbot @ 2020-01-28 12:50 UTC (permalink / raw) To: eparis, jannh, jeffv, keescook, linux-kernel, omosnace, paul, paulmck, sds, selinux, syzkaller-bugs syzbot has found a reproducer for the following crash on: HEAD commit: b0be0eff Merge tag 'x86-pti-2020-01-28' of git://git.kerne.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1432aebee00000 kernel config: https://syzkaller.appspot.com/x/.config?x=9784e57c96a92f20 dashboard link: https://syzkaller.appspot.com/bug?extid=61cba5033e2072d61806 compiler: gcc (GCC) 9.0.0 20181231 (experimental) syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10088e95e00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13fa605ee00000 IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+61cba5033e2072d61806@syzkaller.appspotmail.com ===================================================== WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected 5.5.0-syzkaller #0 Not tainted ----------------------------------------------------- syz-executor305/10624 [HC0[0]:SC0[2]:HE1:SE0] is trying to acquire: ffff888098c14098 (&(&s->cache_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline] ffff888098c14098 (&(&s->cache_lock)->rlock){+.+.}, at: sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 and this task is already holding: ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 which would create a new lock dependency: (&(&nf_conntrack_locks[i])->rlock){+.-.} -> (&(&s->cache_lock)->rlock){+.+.} but this new dependency connects a SOFTIRQ-irq-safe lock: (&(&nf_conntrack_locks[i])->rlock){+.-.} ... which became SOFTIRQ-irq-safe at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 nf_conntrack_double_lock.isra.0+0xac/0x100 net/netfilter/nf_conntrack_core.c:134 __nf_conntrack_confirm+0x252/0x1710 net/netfilter/nf_conntrack_core.c:963 nf_conntrack_confirm include/net/netfilter/nf_conntrack_core.h:63 [inline] nf_confirm+0x3e7/0x4d0 net/netfilter/nf_conntrack_proto.c:154 ipv4_confirm+0x14c/0x240 net/netfilter/nf_conntrack_proto.c:169 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline] nf_hook_slow+0xbc/0x1e0 net/netfilter/core.c:512 nf_hook include/linux/netfilter.h:262 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] ip_local_deliver+0x352/0x520 net/ipv4/ip_input.c:252 dst_input include/net/dst.h:442 [inline] ip_sublist_rcv_finish+0x9b/0x2d0 net/ipv4/ip_input.c:549 ip_list_rcv_finish net/ipv4/ip_input.c:599 [inline] ip_sublist_rcv+0x5a6/0xa20 net/ipv4/ip_input.c:607 ip_list_rcv+0x37e/0x4bf net/ipv4/ip_input.c:642 __netif_receive_skb_list_ptype net/core/dev.c:5193 [inline] __netif_receive_skb_list_core+0x5fc/0x9d0 net/core/dev.c:5241 __netif_receive_skb_list net/core/dev.c:5293 [inline] netif_receive_skb_list_internal+0x7eb/0xe50 net/core/dev.c:5388 gro_normal_list.part.0+0x1e/0xb0 net/core/dev.c:5499 gro_normal_list net/core/dev.c:6232 [inline] napi_complete_done+0x208/0x510 net/core/dev.c:6220 virtqueue_napi_complete+0x31/0xa0 drivers/net/virtio_net.c:329 virtnet_poll+0xbad/0xe90 drivers/net/virtio_net.c:1432 napi_poll net/core/dev.c:6534 [inline] net_rx_action+0x508/0x1120 net/core/dev.c:6602 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] do_IRQ+0xe3/0x280 arch/x86/kernel/irq.c:263 ret_from_intr+0x0/0x36 native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:690 default_idle_call+0x84/0xb0 kernel/sched/idle.c:94 cpuidle_idle_call kernel/sched/idle.c:154 [inline] do_idle+0x3c8/0x6e0 kernel/sched/idle.c:269 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:361 rest_init+0x23b/0x371 init/main.c:451 arch_call_rest_init+0xe/0x1b start_kernel+0x8a3/0x8e2 init/main.c:785 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:490 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:471 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242 to a SOFTIRQ-irq-unsafe lock: (&(&s->cache_lock)->rlock){+.+.} ... which became SOFTIRQ-irq-unsafe at: ... lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 sidtab_sid2str_put+0xa0/0xc0 security/selinux/ss/sidtab.c:566 sidtab_entry_to_string security/selinux/ss/services.c:1279 [inline] sidtab_entry_to_string+0xf2/0x110 security/selinux/ss/services.c:1266 security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 avc_audit_post_callback+0x102/0x790 security/selinux/avc.c:709 common_lsm_audit+0x5ac/0x1e00 security/lsm_audit.c:466 slow_avc_audit+0x16a/0x1f0 security/selinux/avc.c:782 avc_audit security/selinux/include/avc.h:140 [inline] avc_has_perm+0x543/0x610 security/selinux/avc.c:1185 inode_has_perm+0x1a8/0x230 security/selinux/hooks.c:1631 selinux_mmap_file+0x10a/0x1d0 security/selinux/hooks.c:3701 security_mmap_file+0xa4/0x1e0 security/security.c:1482 vm_mmap_pgoff+0xf0/0x230 mm/util.c:502 vm_mmap+0x94/0xc0 mm/util.c:525 elf_map+0x10a/0x2b0 fs/binfmt_elf.c:377 load_elf_binary+0xd4b/0x5310 fs/binfmt_elf.c:982 search_binary_handler fs/exec.c:1658 [inline] search_binary_handler+0x16d/0x570 fs/exec.c:1635 exec_binprm fs/exec.c:1701 [inline] __do_execve_file.isra.0+0x1329/0x22b0 fs/exec.c:1821 do_execveat_common fs/exec.c:1867 [inline] do_execve fs/exec.c:1884 [inline] __do_sys_execve fs/exec.c:1960 [inline] __se_sys_execve fs/exec.c:1955 [inline] __x64_sys_execve+0x8f/0xc0 fs/exec.c:1955 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&(&s->cache_lock)->rlock); local_irq_disable(); lock(&(&nf_conntrack_locks[i])->rlock); lock(&(&s->cache_lock)->rlock); <Interrupt> lock(&(&nf_conntrack_locks[i])->rlock); *** DEADLOCK *** 4 locks held by syz-executor305/10624: #0: ffffffff8c1acc68 (&table[i].mutex){+.+.}, at: nfnl_lock net/netfilter/nfnetlink.c:62 [inline] #0: ffffffff8c1acc68 (&table[i].mutex){+.+.}, at: nfnetlink_rcv_msg+0x9ee/0xfb0 net/netfilter/nfnetlink.c:224 #1: ffff8880836415d8 (nlk_cb_mutex-NETFILTER){+.+.}, at: netlink_dump+0xe7/0xfb0 net/netlink/af_netlink.c:2199 #2: ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] #2: ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 #3: ffffffff8b7df008 (&selinux_ss.policy_rwlock){.+.?}, at: security_sid_to_context_core+0x1ca/0x3c0 security/selinux/ss/services.c:1344 the dependencies between SOFTIRQ-irq-safe lock and the holding lock: -> (&(&nf_conntrack_locks[i])->rlock){+.-.} { HARDIRQ-ON-W at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 get_next_corpse net/netfilter/nf_conntrack_core.c:2001 [inline] nf_ct_iterate_cleanup+0x1d2/0x4e0 net/netfilter/nf_conntrack_core.c:2035 nf_ct_iterate_destroy+0x12e/0x160 net/netfilter/nf_conntrack_core.c:2162 nf_conntrack_helper_unregister+0x111/0x160 net/netfilter/nf_conntrack_helper.c:469 nf_conntrack_helpers_unregister net/netfilter/nf_conntrack_helper.c:532 [inline] nf_conntrack_helpers_register+0xaa/0xe0 net/netfilter/nf_conntrack_helper.c:523 nf_conntrack_sip_init+0x266/0x2a4 net/netfilter/nf_conntrack_sip.c:1693 do_one_initcall+0x120/0x820 init/main.c:939 do_initcall_level init/main.c:1007 [inline] do_initcalls init/main.c:1015 [inline] do_basic_setup init/main.c:1032 [inline] kernel_init_freeable+0x4ca/0x570 init/main.c:1203 kernel_init+0x12/0x1bf init/main.c:1110 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 IN-SOFTIRQ-W at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 nf_conntrack_double_lock.isra.0+0xac/0x100 net/netfilter/nf_conntrack_core.c:134 __nf_conntrack_confirm+0x252/0x1710 net/netfilter/nf_conntrack_core.c:963 nf_conntrack_confirm include/net/netfilter/nf_conntrack_core.h:63 [inline] nf_confirm+0x3e7/0x4d0 net/netfilter/nf_conntrack_proto.c:154 ipv4_confirm+0x14c/0x240 net/netfilter/nf_conntrack_proto.c:169 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline] nf_hook_slow+0xbc/0x1e0 net/netfilter/core.c:512 nf_hook include/linux/netfilter.h:262 [inline] NF_HOOK include/linux/netfilter.h:305 [inline] ip_local_deliver+0x352/0x520 net/ipv4/ip_input.c:252 dst_input include/net/dst.h:442 [inline] ip_sublist_rcv_finish+0x9b/0x2d0 net/ipv4/ip_input.c:549 ip_list_rcv_finish net/ipv4/ip_input.c:599 [inline] ip_sublist_rcv+0x5a6/0xa20 net/ipv4/ip_input.c:607 ip_list_rcv+0x37e/0x4bf net/ipv4/ip_input.c:642 __netif_receive_skb_list_ptype net/core/dev.c:5193 [inline] __netif_receive_skb_list_core+0x5fc/0x9d0 net/core/dev.c:5241 __netif_receive_skb_list net/core/dev.c:5293 [inline] netif_receive_skb_list_internal+0x7eb/0xe50 net/core/dev.c:5388 gro_normal_list.part.0+0x1e/0xb0 net/core/dev.c:5499 gro_normal_list net/core/dev.c:6232 [inline] napi_complete_done+0x208/0x510 net/core/dev.c:6220 virtqueue_napi_complete+0x31/0xa0 drivers/net/virtio_net.c:329 virtnet_poll+0xbad/0xe90 drivers/net/virtio_net.c:1432 napi_poll net/core/dev.c:6534 [inline] net_rx_action+0x508/0x1120 net/core/dev.c:6602 __do_softirq+0x262/0x98c kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0x19b/0x1e0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] do_IRQ+0xe3/0x280 arch/x86/kernel/irq.c:263 ret_from_intr+0x0/0x36 native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:690 default_idle_call+0x84/0xb0 kernel/sched/idle.c:94 cpuidle_idle_call kernel/sched/idle.c:154 [inline] do_idle+0x3c8/0x6e0 kernel/sched/idle.c:269 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:361 rest_init+0x23b/0x371 init/main.c:451 arch_call_rest_init+0xe/0x1b start_kernel+0x8a3/0x8e2 init/main.c:785 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:490 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:471 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242 INITIAL USE at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 get_next_corpse net/netfilter/nf_conntrack_core.c:2001 [inline] nf_ct_iterate_cleanup+0x1d2/0x4e0 net/netfilter/nf_conntrack_core.c:2035 nf_ct_iterate_destroy+0x12e/0x160 net/netfilter/nf_conntrack_core.c:2162 nf_conntrack_helper_unregister+0x111/0x160 net/netfilter/nf_conntrack_helper.c:469 nf_conntrack_helpers_unregister net/netfilter/nf_conntrack_helper.c:532 [inline] nf_conntrack_helpers_register+0xaa/0xe0 net/netfilter/nf_conntrack_helper.c:523 nf_conntrack_sip_init+0x266/0x2a4 net/netfilter/nf_conntrack_sip.c:1693 do_one_initcall+0x120/0x820 init/main.c:939 do_initcall_level init/main.c:1007 [inline] do_initcalls init/main.c:1015 [inline] do_basic_setup init/main.c:1032 [inline] kernel_init_freeable+0x4ca/0x570 init/main.c:1203 kernel_init+0x12/0x1bf init/main.c:1110 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352 } ... key at: [<ffffffff8c1ad440>] __key.79496+0x0/0x40 ... acquired at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 sidtab_sid2str_put+0xa0/0xc0 security/selinux/ss/sidtab.c:566 sidtab_entry_to_string security/selinux/ss/services.c:1279 [inline] sidtab_entry_to_string+0xf2/0x110 security/selinux/ss/services.c:1266 security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 selinux_secid_to_secctx+0x2d/0x40 security/selinux/hooks.c:6451 security_secid_to_secctx+0x75/0xc0 security/security.c:1950 ctnetlink_dump_secctx.isra.0+0x8c/0x330 net/netfilter/nf_conntrack_netlink.c:335 ctnetlink_dump_info net/netfilter/nf_conntrack_netlink.c:531 [inline] ctnetlink_fill_info+0x750/0xd40 net/netfilter/nf_conntrack_netlink.c:591 ctnetlink_dump_table+0x68c/0x1130 net/netfilter/nf_conntrack_netlink.c:979 netlink_dump+0x558/0xfb0 net/netlink/af_netlink.c:2244 __netlink_dump_start+0x66a/0x930 net/netlink/af_netlink.c:2352 netlink_dump_start include/linux/netlink.h:233 [inline] ctnetlink_get_conntrack+0x55e/0x6a0 net/netfilter/nf_conntrack_netlink.c:1355 nfnetlink_rcv_msg+0xcf2/0xfb0 net/netfilter/nfnetlink.c:229 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477 nfnetlink_rcv+0x1ba/0x460 net/netfilter/nfnetlink.c:563 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x58c/0x7d0 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:639 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:659 ____sys_sendmsg+0x753/0x880 net/socket.c:2330 ___sys_sendmsg+0x100/0x170 net/socket.c:2384 __sys_sendmsg+0x105/0x1d0 net/socket.c:2417 __do_sys_sendmsg net/socket.c:2426 [inline] __se_sys_sendmsg net/socket.c:2424 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2424 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe the dependencies between the lock to be acquired and SOFTIRQ-irq-unsafe lock: -> (&(&s->cache_lock)->rlock){+.+.} { HARDIRQ-ON-W at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 sidtab_sid2str_put+0xa0/0xc0 security/selinux/ss/sidtab.c:566 sidtab_entry_to_string security/selinux/ss/services.c:1279 [inline] sidtab_entry_to_string+0xf2/0x110 security/selinux/ss/services.c:1266 security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 avc_audit_post_callback+0x102/0x790 security/selinux/avc.c:709 common_lsm_audit+0x5ac/0x1e00 security/lsm_audit.c:466 slow_avc_audit+0x16a/0x1f0 security/selinux/avc.c:782 avc_audit security/selinux/include/avc.h:140 [inline] avc_has_perm+0x543/0x610 security/selinux/avc.c:1185 inode_has_perm+0x1a8/0x230 security/selinux/hooks.c:1631 selinux_mmap_file+0x10a/0x1d0 security/selinux/hooks.c:3701 security_mmap_file+0xa4/0x1e0 security/security.c:1482 vm_mmap_pgoff+0xf0/0x230 mm/util.c:502 vm_mmap+0x94/0xc0 mm/util.c:525 elf_map+0x10a/0x2b0 fs/binfmt_elf.c:377 load_elf_binary+0xd4b/0x5310 fs/binfmt_elf.c:982 search_binary_handler fs/exec.c:1658 [inline] search_binary_handler+0x16d/0x570 fs/exec.c:1635 exec_binprm fs/exec.c:1701 [inline] __do_execve_file.isra.0+0x1329/0x22b0 fs/exec.c:1821 do_execveat_common fs/exec.c:1867 [inline] do_execve fs/exec.c:1884 [inline] __do_sys_execve fs/exec.c:1960 [inline] __se_sys_execve fs/exec.c:1955 [inline] __x64_sys_execve+0x8f/0xc0 fs/exec.c:1955 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe SOFTIRQ-ON-W at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 sidtab_sid2str_put+0xa0/0xc0 security/selinux/ss/sidtab.c:566 sidtab_entry_to_string security/selinux/ss/services.c:1279 [inline] sidtab_entry_to_string+0xf2/0x110 security/selinux/ss/services.c:1266 security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 avc_audit_post_callback+0x102/0x790 security/selinux/avc.c:709 common_lsm_audit+0x5ac/0x1e00 security/lsm_audit.c:466 slow_avc_audit+0x16a/0x1f0 security/selinux/avc.c:782 avc_audit security/selinux/include/avc.h:140 [inline] avc_has_perm+0x543/0x610 security/selinux/avc.c:1185 inode_has_perm+0x1a8/0x230 security/selinux/hooks.c:1631 selinux_mmap_file+0x10a/0x1d0 security/selinux/hooks.c:3701 security_mmap_file+0xa4/0x1e0 security/security.c:1482 vm_mmap_pgoff+0xf0/0x230 mm/util.c:502 vm_mmap+0x94/0xc0 mm/util.c:525 elf_map+0x10a/0x2b0 fs/binfmt_elf.c:377 load_elf_binary+0xd4b/0x5310 fs/binfmt_elf.c:982 search_binary_handler fs/exec.c:1658 [inline] search_binary_handler+0x16d/0x570 fs/exec.c:1635 exec_binprm fs/exec.c:1701 [inline] __do_execve_file.isra.0+0x1329/0x22b0 fs/exec.c:1821 do_execveat_common fs/exec.c:1867 [inline] do_execve fs/exec.c:1884 [inline] __do_sys_execve fs/exec.c:1960 [inline] __se_sys_execve fs/exec.c:1955 [inline] __x64_sys_execve+0x8f/0xc0 fs/exec.c:1955 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe INITIAL USE at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 sidtab_sid2str_put+0xa0/0xc0 security/selinux/ss/sidtab.c:566 sidtab_entry_to_string security/selinux/ss/services.c:1279 [inline] sidtab_entry_to_string+0xf2/0x110 security/selinux/ss/services.c:1266 security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 avc_audit_post_callback+0x102/0x790 security/selinux/avc.c:709 common_lsm_audit+0x5ac/0x1e00 security/lsm_audit.c:466 slow_avc_audit+0x16a/0x1f0 security/selinux/avc.c:782 avc_audit security/selinux/include/avc.h:140 [inline] avc_has_perm+0x543/0x610 security/selinux/avc.c:1185 inode_has_perm+0x1a8/0x230 security/selinux/hooks.c:1631 selinux_mmap_file+0x10a/0x1d0 security/selinux/hooks.c:3701 security_mmap_file+0xa4/0x1e0 security/security.c:1482 vm_mmap_pgoff+0xf0/0x230 mm/util.c:502 vm_mmap+0x94/0xc0 mm/util.c:525 elf_map+0x10a/0x2b0 fs/binfmt_elf.c:377 load_elf_binary+0xd4b/0x5310 fs/binfmt_elf.c:982 search_binary_handler fs/exec.c:1658 [inline] search_binary_handler+0x16d/0x570 fs/exec.c:1635 exec_binprm fs/exec.c:1701 [inline] __do_execve_file.isra.0+0x1329/0x22b0 fs/exec.c:1821 do_execveat_common fs/exec.c:1867 [inline] do_execve fs/exec.c:1884 [inline] __do_sys_execve fs/exec.c:1960 [inline] __se_sys_execve fs/exec.c:1955 [inline] __x64_sys_execve+0x8f/0xc0 fs/exec.c:1955 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe } ... key at: [<ffffffff8b7dec80>] __key.69173+0x0/0x40 ... acquired at: lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 sidtab_sid2str_put+0xa0/0xc0 security/selinux/ss/sidtab.c:566 sidtab_entry_to_string security/selinux/ss/services.c:1279 [inline] sidtab_entry_to_string+0xf2/0x110 security/selinux/ss/services.c:1266 security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 selinux_secid_to_secctx+0x2d/0x40 security/selinux/hooks.c:6451 security_secid_to_secctx+0x75/0xc0 security/security.c:1950 ctnetlink_dump_secctx.isra.0+0x8c/0x330 net/netfilter/nf_conntrack_netlink.c:335 ctnetlink_dump_info net/netfilter/nf_conntrack_netlink.c:531 [inline] ctnetlink_fill_info+0x750/0xd40 net/netfilter/nf_conntrack_netlink.c:591 ctnetlink_dump_table+0x68c/0x1130 net/netfilter/nf_conntrack_netlink.c:979 netlink_dump+0x558/0xfb0 net/netlink/af_netlink.c:2244 __netlink_dump_start+0x66a/0x930 net/netlink/af_netlink.c:2352 netlink_dump_start include/linux/netlink.h:233 [inline] ctnetlink_get_conntrack+0x55e/0x6a0 net/netfilter/nf_conntrack_netlink.c:1355 nfnetlink_rcv_msg+0xcf2/0xfb0 net/netfilter/nfnetlink.c:229 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477 nfnetlink_rcv+0x1ba/0x460 net/netfilter/nfnetlink.c:563 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x58c/0x7d0 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:639 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:659 ____sys_sendmsg+0x753/0x880 net/socket.c:2330 ___sys_sendmsg+0x100/0x170 net/socket.c:2384 __sys_sendmsg+0x105/0x1d0 net/socket.c:2417 __do_sys_sendmsg net/socket.c:2426 [inline] __se_sys_sendmsg net/socket.c:2424 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2424 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe stack backtrace: CPU: 1 PID: 10624 Comm: syz-executor305 Not tainted 5.5.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x197/0x210 lib/dump_stack.c:118 print_bad_irq_dependency kernel/locking/lockdep.c:2094 [inline] check_irq_usage.cold+0x586/0x6fe kernel/locking/lockdep.c:2292 check_prev_add kernel/locking/lockdep.c:2479 [inline] check_prevs_add kernel/locking/lockdep.c:2580 [inline] validate_chain kernel/locking/lockdep.c:2970 [inline] __lock_acquire+0x25b4/0x4a00 kernel/locking/lockdep.c:3954 lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 sidtab_sid2str_put+0xa0/0xc0 security/selinux/ss/sidtab.c:566 sidtab_entry_to_string security/selinux/ss/services.c:1279 [inline] sidtab_entry_to_string+0xf2/0x110 security/selinux/ss/services.c:1266 security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 selinux_secid_to_secctx+0x2d/0x40 security/selinux/hooks.c:6451 security_secid_to_secctx+0x75/0xc0 security/security.c:1950 ctnetlink_dump_secctx.isra.0+0x8c/0x330 net/netfilter/nf_conntrack_netlink.c:335 ctnetlink_dump_info net/netfilter/nf_conntrack_netlink.c:531 [inline] ctnetlink_fill_info+0x750/0xd40 net/netfilter/nf_conntrack_netlink.c:591 ctnetlink_dump_table+0x68c/0x1130 net/netfilter/nf_conntrack_netlink.c:979 netlink_dump+0x558/0xfb0 net/netlink/af_netlink.c:2244 __netlink_dump_start+0x66a/0x930 net/netlink/af_netlink.c:2352 netlink_dump_start include/linux/netlink.h:233 [inline] ctnetlink_get_conntrack+0x55e/0x6a0 net/netfilter/nf_conntrack_netlink.c:1355 nfnetlink_rcv_msg+0xcf2/0xfb0 net/netfilter/nfnetlink.c:229 netlink_rcv_skb+0x177/0x450 net/netlink/af_netlink.c:2477 nfnetlink_rcv+0x1ba/0x460 net/netfilter/nfnetlink.c:563 netlink_unicast_kernel net/netlink/af_netlink.c:1302 [inline] netlink_unicast+0x58c/0x7d0 net/netlink/af_netlink.c:1328 netlink_sendmsg+0x91c/0xea0 net/netlink/af_netlink.c:1917 sock_sendmsg_nosec net/socket.c:639 [inline] sock_sendmsg+0xd7/0x130 net/socket.c:659 ____sys_sendmsg+0x753/0x880 net/socket.c:2330 ___sys_sendmsg+0x100/0x170 net/socket.c:2384 __sys_sendmsg+0x105/0x1d0 net/socket.c:2417 __do_sys_sendmsg net/socket.c:2426 [inline] __se_sys_sendmsg net/socket.c:2424 [inline] __x64_sys_sendmsg+0x78/0xb0 net/socket.c:2424 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4401e9 Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 fb 13 fc ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007ffe6ca42208 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00000000004002c8 RCX: 00000000004401e9 RDX: 0000000000000000 RSI: 0000000020d65000 RDI: 0000000000000003 RBP: 00000000006ca018 R08: 0000000000000000 R09: 0000000 ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: possible deadlock in sidtab_sid2str_put 2020-01-28 12:50 ` syzbot @ 2020-01-28 13:39 ` Paul Moore 2020-01-28 13:45 ` Stephen Smalley 2020-01-28 13:51 ` Ondrej Mosnacek 0 siblings, 2 replies; 11+ messages in thread From: Paul Moore @ 2020-01-28 13:39 UTC (permalink / raw) To: jeffv, omosnace, Stephen Smalley Cc: Eric Paris, jannh, keescook, linux-kernel, paulmck, selinux, syzkaller-bugs, syzbot On Tue, Jan 28, 2020 at 7:50 AM syzbot <syzbot+61cba5033e2072d61806@syzkaller.appspotmail.com> wrote: > > syzbot has found a reproducer for the following crash on: > > HEAD commit: b0be0eff Merge tag 'x86-pti-2020-01-28' of git://git.kerne.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=1432aebee00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=9784e57c96a92f20 > dashboard link: https://syzkaller.appspot.com/bug?extid=61cba5033e2072d61806 > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10088e95e00000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13fa605ee00000 > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+61cba5033e2072d61806@syzkaller.appspotmail.com > > ===================================================== > WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected > 5.5.0-syzkaller #0 Not tainted > ----------------------------------------------------- > syz-executor305/10624 [HC0[0]:SC0[2]:HE1:SE0] is trying to acquire: > ffff888098c14098 (&(&s->cache_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline] > ffff888098c14098 (&(&s->cache_lock)->rlock){+.+.}, at: sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 > > and this task is already holding: > ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] > ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 > which would create a new lock dependency: > (&(&nf_conntrack_locks[i])->rlock){+.-.} -> (&(&s->cache_lock)->rlock){+.+.} > > but this new dependency connects a SOFTIRQ-irq-safe lock: > (&(&nf_conntrack_locks[i])->rlock){+.-.} > > ... which became SOFTIRQ-irq-safe at: > lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 > __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] > _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 > spin_lock include/linux/spinlock.h:338 [inline] > nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 ... > to a SOFTIRQ-irq-unsafe lock: > (&(&s->cache_lock)->rlock){+.+.} > > ... which became SOFTIRQ-irq-unsafe at: > ... > lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 > __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] > _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 > spin_lock include/linux/spinlock.h:338 [inline] > sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 > sidtab_sid2str_put+0xa0/0xc0 security/selinux/ss/sidtab.c:566 > sidtab_entry_to_string security/selinux/ss/services.c:1279 [inline] > sidtab_entry_to_string+0xf2/0x110 security/selinux/ss/services.c:1266 > security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 > security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 > avc_audit_post_callback+0x102/0x790 security/selinux/avc.c:709 > common_lsm_audit+0x5ac/0x1e00 security/lsm_audit.c:466 > slow_avc_audit+0x16a/0x1f0 security/selinux/avc.c:782 > avc_audit security/selinux/include/avc.h:140 [inline] > avc_has_perm+0x543/0x610 security/selinux/avc.c:1185 > inode_has_perm+0x1a8/0x230 security/selinux/hooks.c:1631 > selinux_mmap_file+0x10a/0x1d0 security/selinux/hooks.c:3701 > security_mmap_file+0xa4/0x1e0 security/security.c:1482 > vm_mmap_pgoff+0xf0/0x230 mm/util.c:502 ... > other info that might help us debug this: > > Possible interrupt unsafe locking scenario: > > CPU0 CPU1 > ---- ---- > lock(&(&s->cache_lock)->rlock); > local_irq_disable(); > lock(&(&nf_conntrack_locks[i])->rlock); > lock(&(&s->cache_lock)->rlock); > <Interrupt> > lock(&(&nf_conntrack_locks[i])->rlock); > > *** DEADLOCK *** > > 4 locks held by syz-executor305/10624: > #0: ffffffff8c1acc68 (&table[i].mutex){+.+.}, at: nfnl_lock net/netfilter/nfnetlink.c:62 [inline] > #0: ffffffff8c1acc68 (&table[i].mutex){+.+.}, at: nfnetlink_rcv_msg+0x9ee/0xfb0 net/netfilter/nfnetlink.c:224 > #1: ffff8880836415d8 (nlk_cb_mutex-NETFILTER){+.+.}, at: netlink_dump+0xe7/0xfb0 net/netlink/af_netlink.c:2199 > #2: ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] > #2: ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 > #3: ffffffff8b7df008 (&selinux_ss.policy_rwlock){.+.?}, at: security_sid_to_context_core+0x1ca/0x3c0 security/selinux/ss/services.c:1344 I think this is going to be tricky to fix due to the differing contexts from which sidtab_sid2str_put() may be called. We already have a check for !in_task() in sidtab_sid2str_put(), do we want to add a check for !in_serving_softirq() too? -- paul moore www.paul-moore.com ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: possible deadlock in sidtab_sid2str_put 2020-01-28 13:39 ` Paul Moore @ 2020-01-28 13:45 ` Stephen Smalley 2020-01-28 14:26 ` Ondrej Mosnacek 2020-01-28 13:51 ` Ondrej Mosnacek 1 sibling, 1 reply; 11+ messages in thread From: Stephen Smalley @ 2020-01-28 13:45 UTC (permalink / raw) To: Paul Moore, jeffv, omosnace Cc: Eric Paris, jannh, keescook, linux-kernel, paulmck, selinux, syzkaller-bugs, syzbot On 1/28/20 8:39 AM, Paul Moore wrote: > On Tue, Jan 28, 2020 at 7:50 AM syzbot > <syzbot+61cba5033e2072d61806@syzkaller.appspotmail.com> wrote: >> >> syzbot has found a reproducer for the following crash on: >> >> HEAD commit: b0be0eff Merge tag 'x86-pti-2020-01-28' of git://git.kerne.. >> git tree: upstream >> console output: https://syzkaller.appspot.com/x/log.txt?x=1432aebee00000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=9784e57c96a92f20 >> dashboard link: https://syzkaller.appspot.com/bug?extid=61cba5033e2072d61806 >> compiler: gcc (GCC) 9.0.0 20181231 (experimental) >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10088e95e00000 >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13fa605ee00000 >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+61cba5033e2072d61806@syzkaller.appspotmail.com >> >> ===================================================== >> WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected >> 5.5.0-syzkaller #0 Not tainted >> ----------------------------------------------------- >> syz-executor305/10624 [HC0[0]:SC0[2]:HE1:SE0] is trying to acquire: >> ffff888098c14098 (&(&s->cache_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline] >> ffff888098c14098 (&(&s->cache_lock)->rlock){+.+.}, at: sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 >> >> and this task is already holding: >> ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] >> ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 >> which would create a new lock dependency: >> (&(&nf_conntrack_locks[i])->rlock){+.-.} -> (&(&s->cache_lock)->rlock){+.+.} >> >> but this new dependency connects a SOFTIRQ-irq-safe lock: >> (&(&nf_conntrack_locks[i])->rlock){+.-.} >> >> ... which became SOFTIRQ-irq-safe at: >> lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 >> __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] >> _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 >> spin_lock include/linux/spinlock.h:338 [inline] >> nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 > > ... > >> to a SOFTIRQ-irq-unsafe lock: >> (&(&s->cache_lock)->rlock){+.+.} >> >> ... which became SOFTIRQ-irq-unsafe at: >> ... >> lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 >> __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] >> _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 >> spin_lock include/linux/spinlock.h:338 [inline] >> sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 >> sidtab_sid2str_put+0xa0/0xc0 security/selinux/ss/sidtab.c:566 >> sidtab_entry_to_string security/selinux/ss/services.c:1279 [inline] >> sidtab_entry_to_string+0xf2/0x110 security/selinux/ss/services.c:1266 >> security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 >> security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 >> avc_audit_post_callback+0x102/0x790 security/selinux/avc.c:709 >> common_lsm_audit+0x5ac/0x1e00 security/lsm_audit.c:466 >> slow_avc_audit+0x16a/0x1f0 security/selinux/avc.c:782 >> avc_audit security/selinux/include/avc.h:140 [inline] >> avc_has_perm+0x543/0x610 security/selinux/avc.c:1185 >> inode_has_perm+0x1a8/0x230 security/selinux/hooks.c:1631 >> selinux_mmap_file+0x10a/0x1d0 security/selinux/hooks.c:3701 >> security_mmap_file+0xa4/0x1e0 security/security.c:1482 >> vm_mmap_pgoff+0xf0/0x230 mm/util.c:502 > > ... > >> other info that might help us debug this: >> >> Possible interrupt unsafe locking scenario: >> >> CPU0 CPU1 >> ---- ---- >> lock(&(&s->cache_lock)->rlock); >> local_irq_disable(); >> lock(&(&nf_conntrack_locks[i])->rlock); >> lock(&(&s->cache_lock)->rlock); >> <Interrupt> >> lock(&(&nf_conntrack_locks[i])->rlock); >> >> *** DEADLOCK *** >> >> 4 locks held by syz-executor305/10624: >> #0: ffffffff8c1acc68 (&table[i].mutex){+.+.}, at: nfnl_lock net/netfilter/nfnetlink.c:62 [inline] >> #0: ffffffff8c1acc68 (&table[i].mutex){+.+.}, at: nfnetlink_rcv_msg+0x9ee/0xfb0 net/netfilter/nfnetlink.c:224 >> #1: ffff8880836415d8 (nlk_cb_mutex-NETFILTER){+.+.}, at: netlink_dump+0xe7/0xfb0 net/netlink/af_netlink.c:2199 >> #2: ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] >> #2: ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 >> #3: ffffffff8b7df008 (&selinux_ss.policy_rwlock){.+.?}, at: security_sid_to_context_core+0x1ca/0x3c0 security/selinux/ss/services.c:1344 > > I think this is going to be tricky to fix due to the differing > contexts from which sidtab_sid2str_put() may be called. We already > have a check for !in_task() in sidtab_sid2str_put(), do we want to add > a check for !in_serving_softirq() too? No, we should just use spin_lock_irqsave/unlock_irqrestore() IMHO, but that then means we need to re-evaluate the performance gain of this change. ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: possible deadlock in sidtab_sid2str_put 2020-01-28 13:45 ` Stephen Smalley @ 2020-01-28 14:26 ` Ondrej Mosnacek 2020-01-28 15:45 ` Paul Moore 0 siblings, 1 reply; 11+ messages in thread From: Ondrej Mosnacek @ 2020-01-28 14:26 UTC (permalink / raw) To: Stephen Smalley Cc: Paul Moore, Jeff Vander Stoep, Eric Paris, Jann Horn, Kees Cook, Linux kernel mailing list, Paul E. McKenney, SElinux list, syzkaller-bugs, syzbot On Tue, Jan 28, 2020 at 2:44 PM Stephen Smalley <sds@tycho.nsa.gov> wrote: > On 1/28/20 8:39 AM, Paul Moore wrote: > > On Tue, Jan 28, 2020 at 7:50 AM syzbot > > <syzbot+61cba5033e2072d61806@syzkaller.appspotmail.com> wrote: > >> > >> syzbot has found a reproducer for the following crash on: > >> > >> HEAD commit: b0be0eff Merge tag 'x86-pti-2020-01-28' of git://git.kerne.. > >> git tree: upstream > >> console output: https://syzkaller.appspot.com/x/log.txt?x=1432aebee00000 > >> kernel config: https://syzkaller.appspot.com/x/.config?x=9784e57c96a92f20 > >> dashboard link: https://syzkaller.appspot.com/bug?extid=61cba5033e2072d61806 > >> compiler: gcc (GCC) 9.0.0 20181231 (experimental) > >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10088e95e00000 > >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13fa605ee00000 > >> > >> IMPORTANT: if you fix the bug, please add the following tag to the commit: > >> Reported-by: syzbot+61cba5033e2072d61806@syzkaller.appspotmail.com > >> > >> ===================================================== > >> WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected > >> 5.5.0-syzkaller #0 Not tainted > >> ----------------------------------------------------- > >> syz-executor305/10624 [HC0[0]:SC0[2]:HE1:SE0] is trying to acquire: > >> ffff888098c14098 (&(&s->cache_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline] > >> ffff888098c14098 (&(&s->cache_lock)->rlock){+.+.}, at: sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 > >> > >> and this task is already holding: > >> ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] > >> ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 > >> which would create a new lock dependency: > >> (&(&nf_conntrack_locks[i])->rlock){+.-.} -> (&(&s->cache_lock)->rlock){+.+.} > >> > >> but this new dependency connects a SOFTIRQ-irq-safe lock: > >> (&(&nf_conntrack_locks[i])->rlock){+.-.} > >> > >> ... which became SOFTIRQ-irq-safe at: > >> lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 > >> __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] > >> _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 > >> spin_lock include/linux/spinlock.h:338 [inline] > >> nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 > > > > ... > > > >> to a SOFTIRQ-irq-unsafe lock: > >> (&(&s->cache_lock)->rlock){+.+.} > >> > >> ... which became SOFTIRQ-irq-unsafe at: > >> ... > >> lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 > >> __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] > >> _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 > >> spin_lock include/linux/spinlock.h:338 [inline] > >> sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 > >> sidtab_sid2str_put+0xa0/0xc0 security/selinux/ss/sidtab.c:566 > >> sidtab_entry_to_string security/selinux/ss/services.c:1279 [inline] > >> sidtab_entry_to_string+0xf2/0x110 security/selinux/ss/services.c:1266 > >> security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 > >> security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 > >> avc_audit_post_callback+0x102/0x790 security/selinux/avc.c:709 > >> common_lsm_audit+0x5ac/0x1e00 security/lsm_audit.c:466 > >> slow_avc_audit+0x16a/0x1f0 security/selinux/avc.c:782 > >> avc_audit security/selinux/include/avc.h:140 [inline] > >> avc_has_perm+0x543/0x610 security/selinux/avc.c:1185 > >> inode_has_perm+0x1a8/0x230 security/selinux/hooks.c:1631 > >> selinux_mmap_file+0x10a/0x1d0 security/selinux/hooks.c:3701 > >> security_mmap_file+0xa4/0x1e0 security/security.c:1482 > >> vm_mmap_pgoff+0xf0/0x230 mm/util.c:502 > > > > ... > > > >> other info that might help us debug this: > >> > >> Possible interrupt unsafe locking scenario: > >> > >> CPU0 CPU1 > >> ---- ---- > >> lock(&(&s->cache_lock)->rlock); > >> local_irq_disable(); > >> lock(&(&nf_conntrack_locks[i])->rlock); > >> lock(&(&s->cache_lock)->rlock); > >> <Interrupt> > >> lock(&(&nf_conntrack_locks[i])->rlock); > >> > >> *** DEADLOCK *** > >> > >> 4 locks held by syz-executor305/10624: > >> #0: ffffffff8c1acc68 (&table[i].mutex){+.+.}, at: nfnl_lock net/netfilter/nfnetlink.c:62 [inline] > >> #0: ffffffff8c1acc68 (&table[i].mutex){+.+.}, at: nfnetlink_rcv_msg+0x9ee/0xfb0 net/netfilter/nfnetlink.c:224 > >> #1: ffff8880836415d8 (nlk_cb_mutex-NETFILTER){+.+.}, at: netlink_dump+0xe7/0xfb0 net/netlink/af_netlink.c:2199 > >> #2: ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] > >> #2: ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 > >> #3: ffffffff8b7df008 (&selinux_ss.policy_rwlock){.+.?}, at: security_sid_to_context_core+0x1ca/0x3c0 security/selinux/ss/services.c:1344 > > > > I think this is going to be tricky to fix due to the differing > > contexts from which sidtab_sid2str_put() may be called. We already > > have a check for !in_task() in sidtab_sid2str_put(), do we want to add > > a check for !in_serving_softirq() too? > > No, we should just use spin_lock_irqsave/unlock_irqrestore() IMHO, but > that then means we need to re-evaluate the performance gain of this change. I just tested a patch that switches to the IRQ-disabling locking under the systemd-journald scenario from [1] and the impact seems not that bad - the security_secid_to_secctx() function only takes up 3.18% of total run time vs. ~2% I reported in the original patch (d97bd23c2d7d). I'll post the patch shortly. [1] https://bugzilla.redhat.com/show_bug.cgi?id=1733259, i.e.: cat /dev/urandom | base64 | logger & timeout 30s perf record -p $(pidof systemd-journald) -a -g -- Ondrej Mosnacek <omosnace at redhat dot com> Software Engineer, Security Technologies Red Hat, Inc. ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: possible deadlock in sidtab_sid2str_put 2020-01-28 14:26 ` Ondrej Mosnacek @ 2020-01-28 15:45 ` Paul Moore 2020-01-28 16:30 ` Ondrej Mosnacek 0 siblings, 1 reply; 11+ messages in thread From: Paul Moore @ 2020-01-28 15:45 UTC (permalink / raw) To: Ondrej Mosnacek Cc: Stephen Smalley, Jeff Vander Stoep, Eric Paris, Jann Horn, Kees Cook, Linux kernel mailing list, Paul E. McKenney, SElinux list, syzkaller-bugs, syzbot On Tue, Jan 28, 2020 at 9:27 AM Ondrej Mosnacek <omosnace@redhat.com> wrote: > On Tue, Jan 28, 2020 at 2:44 PM Stephen Smalley <sds@tycho.nsa.gov> wrote: > > On 1/28/20 8:39 AM, Paul Moore wrote: > > > On Tue, Jan 28, 2020 at 7:50 AM syzbot > > > <syzbot+61cba5033e2072d61806@syzkaller.appspotmail.com> wrote: > > >> > > >> syzbot has found a reproducer for the following crash on: > > >> > > >> HEAD commit: b0be0eff Merge tag 'x86-pti-2020-01-28' of git://git.kerne.. > > >> git tree: upstream > > >> console output: https://syzkaller.appspot.com/x/log.txt?x=1432aebee00000 > > >> kernel config: https://syzkaller.appspot.com/x/.config?x=9784e57c96a92f20 > > >> dashboard link: https://syzkaller.appspot.com/bug?extid=61cba5033e2072d61806 > > >> compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10088e95e00000 > > >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13fa605ee00000 > > >> > > >> IMPORTANT: if you fix the bug, please add the following tag to the commit: > > >> Reported-by: syzbot+61cba5033e2072d61806@syzkaller.appspotmail.com > > >> > > >> ===================================================== > > >> WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected > > >> 5.5.0-syzkaller #0 Not tainted > > >> ----------------------------------------------------- > > >> syz-executor305/10624 [HC0[0]:SC0[2]:HE1:SE0] is trying to acquire: > > >> ffff888098c14098 (&(&s->cache_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline] > > >> ffff888098c14098 (&(&s->cache_lock)->rlock){+.+.}, at: sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 > > >> > > >> and this task is already holding: > > >> ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] > > >> ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 > > >> which would create a new lock dependency: > > >> (&(&nf_conntrack_locks[i])->rlock){+.-.} -> (&(&s->cache_lock)->rlock){+.+.} > > >> > > >> but this new dependency connects a SOFTIRQ-irq-safe lock: > > >> (&(&nf_conntrack_locks[i])->rlock){+.-.} > > >> > > >> ... which became SOFTIRQ-irq-safe at: > > >> lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 > > >> __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] > > >> _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 > > >> spin_lock include/linux/spinlock.h:338 [inline] > > >> nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 > > > > > > ... > > > > > >> to a SOFTIRQ-irq-unsafe lock: > > >> (&(&s->cache_lock)->rlock){+.+.} > > >> > > >> ... which became SOFTIRQ-irq-unsafe at: > > >> ... > > >> lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 > > >> __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] > > >> _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 > > >> spin_lock include/linux/spinlock.h:338 [inline] > > >> sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 > > >> sidtab_sid2str_put+0xa0/0xc0 security/selinux/ss/sidtab.c:566 > > >> sidtab_entry_to_string security/selinux/ss/services.c:1279 [inline] > > >> sidtab_entry_to_string+0xf2/0x110 security/selinux/ss/services.c:1266 > > >> security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 > > >> security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 > > >> avc_audit_post_callback+0x102/0x790 security/selinux/avc.c:709 > > >> common_lsm_audit+0x5ac/0x1e00 security/lsm_audit.c:466 > > >> slow_avc_audit+0x16a/0x1f0 security/selinux/avc.c:782 > > >> avc_audit security/selinux/include/avc.h:140 [inline] > > >> avc_has_perm+0x543/0x610 security/selinux/avc.c:1185 > > >> inode_has_perm+0x1a8/0x230 security/selinux/hooks.c:1631 > > >> selinux_mmap_file+0x10a/0x1d0 security/selinux/hooks.c:3701 > > >> security_mmap_file+0xa4/0x1e0 security/security.c:1482 > > >> vm_mmap_pgoff+0xf0/0x230 mm/util.c:502 > > > > > > ... > > > > > >> other info that might help us debug this: > > >> > > >> Possible interrupt unsafe locking scenario: > > >> > > >> CPU0 CPU1 > > >> ---- ---- > > >> lock(&(&s->cache_lock)->rlock); > > >> local_irq_disable(); > > >> lock(&(&nf_conntrack_locks[i])->rlock); > > >> lock(&(&s->cache_lock)->rlock); > > >> <Interrupt> > > >> lock(&(&nf_conntrack_locks[i])->rlock); > > >> > > >> *** DEADLOCK *** > > >> > > >> 4 locks held by syz-executor305/10624: > > >> #0: ffffffff8c1acc68 (&table[i].mutex){+.+.}, at: nfnl_lock net/netfilter/nfnetlink.c:62 [inline] > > >> #0: ffffffff8c1acc68 (&table[i].mutex){+.+.}, at: nfnetlink_rcv_msg+0x9ee/0xfb0 net/netfilter/nfnetlink.c:224 > > >> #1: ffff8880836415d8 (nlk_cb_mutex-NETFILTER){+.+.}, at: netlink_dump+0xe7/0xfb0 net/netlink/af_netlink.c:2199 > > >> #2: ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] > > >> #2: ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 > > >> #3: ffffffff8b7df008 (&selinux_ss.policy_rwlock){.+.?}, at: security_sid_to_context_core+0x1ca/0x3c0 security/selinux/ss/services.c:1344 > > > > > > I think this is going to be tricky to fix due to the differing > > > contexts from which sidtab_sid2str_put() may be called. We already > > > have a check for !in_task() in sidtab_sid2str_put(), do we want to add > > > a check for !in_serving_softirq() too? > > > > No, we should just use spin_lock_irqsave/unlock_irqrestore() IMHO, but > > that then means we need to re-evaluate the performance gain of this change. > > I just tested a patch that switches to the IRQ-disabling locking under > the systemd-journald scenario from [1] and the impact seems not that > bad - the security_secid_to_secctx() function only takes up 3.18% of > total run time vs. ~2% I reported in the original patch > (d97bd23c2d7d). I'll post the patch shortly. > > [1] https://bugzilla.redhat.com/show_bug.cgi?id=1733259, i.e.: > cat /dev/urandom | base64 | logger & > timeout 30s perf record -p $(pidof systemd-journald) -a -g I'm skeptical of the real world impact of disabling IRQs here, although I'm not sure off the top of my head how we could manage a cache (I'm thinking more about adding to, and evicting entries, from the cache) without some form of locking. Perhaps we look into per-cpu caching? -- paul moore www.paul-moore.com ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: possible deadlock in sidtab_sid2str_put 2020-01-28 15:45 ` Paul Moore @ 2020-01-28 16:30 ` Ondrej Mosnacek 2020-01-28 17:29 ` Paul Moore 0 siblings, 1 reply; 11+ messages in thread From: Ondrej Mosnacek @ 2020-01-28 16:30 UTC (permalink / raw) To: Paul Moore Cc: Stephen Smalley, Jeff Vander Stoep, Eric Paris, Jann Horn, Kees Cook, Linux kernel mailing list, Paul E. McKenney, SElinux list, syzkaller-bugs, syzbot [-- Attachment #1: Type: text/plain, Size: 7880 bytes --] On Tue, Jan 28, 2020 at 4:45 PM Paul Moore <paul@paul-moore.com> wrote: > On Tue, Jan 28, 2020 at 9:27 AM Ondrej Mosnacek <omosnace@redhat.com> wrote: > > On Tue, Jan 28, 2020 at 2:44 PM Stephen Smalley <sds@tycho.nsa.gov> wrote: > > > On 1/28/20 8:39 AM, Paul Moore wrote: > > > > On Tue, Jan 28, 2020 at 7:50 AM syzbot > > > > <syzbot+61cba5033e2072d61806@syzkaller.appspotmail.com> wrote: > > > >> > > > >> syzbot has found a reproducer for the following crash on: > > > >> > > > >> HEAD commit: b0be0eff Merge tag 'x86-pti-2020-01-28' of git://git.kerne.. > > > >> git tree: upstream > > > >> console output: https://syzkaller.appspot.com/x/log.txt?x=1432aebee00000 > > > >> kernel config: https://syzkaller.appspot.com/x/.config?x=9784e57c96a92f20 > > > >> dashboard link: https://syzkaller.appspot.com/bug?extid=61cba5033e2072d61806 > > > >> compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > > >> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10088e95e00000 > > > >> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13fa605ee00000 > > > >> > > > >> IMPORTANT: if you fix the bug, please add the following tag to the commit: > > > >> Reported-by: syzbot+61cba5033e2072d61806@syzkaller.appspotmail.com > > > >> > > > >> ===================================================== > > > >> WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected > > > >> 5.5.0-syzkaller #0 Not tainted > > > >> ----------------------------------------------------- > > > >> syz-executor305/10624 [HC0[0]:SC0[2]:HE1:SE0] is trying to acquire: > > > >> ffff888098c14098 (&(&s->cache_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline] > > > >> ffff888098c14098 (&(&s->cache_lock)->rlock){+.+.}, at: sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 > > > >> > > > >> and this task is already holding: > > > >> ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] > > > >> ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 > > > >> which would create a new lock dependency: > > > >> (&(&nf_conntrack_locks[i])->rlock){+.-.} -> (&(&s->cache_lock)->rlock){+.+.} > > > >> > > > >> but this new dependency connects a SOFTIRQ-irq-safe lock: > > > >> (&(&nf_conntrack_locks[i])->rlock){+.-.} > > > >> > > > >> ... which became SOFTIRQ-irq-safe at: > > > >> lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 > > > >> __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] > > > >> _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 > > > >> spin_lock include/linux/spinlock.h:338 [inline] > > > >> nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 > > > > > > > > ... > > > > > > > >> to a SOFTIRQ-irq-unsafe lock: > > > >> (&(&s->cache_lock)->rlock){+.+.} > > > >> > > > >> ... which became SOFTIRQ-irq-unsafe at: > > > >> ... > > > >> lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 > > > >> __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] > > > >> _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 > > > >> spin_lock include/linux/spinlock.h:338 [inline] > > > >> sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 > > > >> sidtab_sid2str_put+0xa0/0xc0 security/selinux/ss/sidtab.c:566 > > > >> sidtab_entry_to_string security/selinux/ss/services.c:1279 [inline] > > > >> sidtab_entry_to_string+0xf2/0x110 security/selinux/ss/services.c:1266 > > > >> security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 > > > >> security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 > > > >> avc_audit_post_callback+0x102/0x790 security/selinux/avc.c:709 > > > >> common_lsm_audit+0x5ac/0x1e00 security/lsm_audit.c:466 > > > >> slow_avc_audit+0x16a/0x1f0 security/selinux/avc.c:782 > > > >> avc_audit security/selinux/include/avc.h:140 [inline] > > > >> avc_has_perm+0x543/0x610 security/selinux/avc.c:1185 > > > >> inode_has_perm+0x1a8/0x230 security/selinux/hooks.c:1631 > > > >> selinux_mmap_file+0x10a/0x1d0 security/selinux/hooks.c:3701 > > > >> security_mmap_file+0xa4/0x1e0 security/security.c:1482 > > > >> vm_mmap_pgoff+0xf0/0x230 mm/util.c:502 > > > > > > > > ... > > > > > > > >> other info that might help us debug this: > > > >> > > > >> Possible interrupt unsafe locking scenario: > > > >> > > > >> CPU0 CPU1 > > > >> ---- ---- > > > >> lock(&(&s->cache_lock)->rlock); > > > >> local_irq_disable(); > > > >> lock(&(&nf_conntrack_locks[i])->rlock); > > > >> lock(&(&s->cache_lock)->rlock); > > > >> <Interrupt> > > > >> lock(&(&nf_conntrack_locks[i])->rlock); > > > >> > > > >> *** DEADLOCK *** > > > >> > > > >> 4 locks held by syz-executor305/10624: > > > >> #0: ffffffff8c1acc68 (&table[i].mutex){+.+.}, at: nfnl_lock net/netfilter/nfnetlink.c:62 [inline] > > > >> #0: ffffffff8c1acc68 (&table[i].mutex){+.+.}, at: nfnetlink_rcv_msg+0x9ee/0xfb0 net/netfilter/nfnetlink.c:224 > > > >> #1: ffff8880836415d8 (nlk_cb_mutex-NETFILTER){+.+.}, at: netlink_dump+0xe7/0xfb0 net/netlink/af_netlink.c:2199 > > > >> #2: ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] > > > >> #2: ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 > > > >> #3: ffffffff8b7df008 (&selinux_ss.policy_rwlock){.+.?}, at: security_sid_to_context_core+0x1ca/0x3c0 security/selinux/ss/services.c:1344 > > > > > > > > I think this is going to be tricky to fix due to the differing > > > > contexts from which sidtab_sid2str_put() may be called. We already > > > > have a check for !in_task() in sidtab_sid2str_put(), do we want to add > > > > a check for !in_serving_softirq() too? > > > > > > No, we should just use spin_lock_irqsave/unlock_irqrestore() IMHO, but > > > that then means we need to re-evaluate the performance gain of this change. > > > > I just tested a patch that switches to the IRQ-disabling locking under > > the systemd-journald scenario from [1] and the impact seems not that > > bad - the security_secid_to_secctx() function only takes up 3.18% of > > total run time vs. ~2% I reported in the original patch > > (d97bd23c2d7d). I'll post the patch shortly. > > > > [1] https://bugzilla.redhat.com/show_bug.cgi?id=1733259, i.e.: > > cat /dev/urandom | base64 | logger & > > timeout 30s perf record -p $(pidof systemd-journald) -a -g > > I'm skeptical of the real world impact of disabling IRQs here, > although I'm not sure off the top of my head how we could manage a > cache (I'm thinking more about adding to, and evicting entries, from > the cache) without some form of locking. Perhaps we look into per-cpu > caching? (I hope the ML won't mind an SVG attachment...) This is a flamegraph of the scenario above, with the sipn_[un]lock_irq{save|restore}() patch applied. You can see that the overhead of locking is not so bad - the kmemdup (which is unavoidable here) still takes up most of the computation time. We can try to find a more clever cache implementation later, but this solution should be still much better than (in case of dense MCS contexts) to comparable to (in case of no MCS categories) no caching. BTW I'm trying to do some final testing of the patch on a multi-CPU system, but the current rawhide 5.5.0-1 kernel seems to have some bug that prevents it from booting on anything with more than one core. I'll see if I can work around it somehow... -- Ondrej Mosnacek <omosnace at redhat dot com> Software Engineer, Security Technologies Red Hat, Inc. [-- Attachment #2: BEAKERLIB_134310003_STORED_flamegraph.svg --] [-- Type: image/svg+xml, Size: 122428 bytes --] ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: possible deadlock in sidtab_sid2str_put 2020-01-28 16:30 ` Ondrej Mosnacek @ 2020-01-28 17:29 ` Paul Moore 2020-02-03 8:46 ` Ondrej Mosnacek 0 siblings, 1 reply; 11+ messages in thread From: Paul Moore @ 2020-01-28 17:29 UTC (permalink / raw) To: Ondrej Mosnacek Cc: Stephen Smalley, Jeff Vander Stoep, Eric Paris, Jann Horn, Kees Cook, Linux kernel mailing list, Paul E. McKenney, SElinux list, syzkaller-bugs, syzbot On Tue, Jan 28, 2020 at 11:31 AM Ondrej Mosnacek <omosnace@redhat.com> wrote: > ... the current rawhide 5.5.0-1 kernel seems to have some bug > that prevents it from booting on anything with more than one core. > I'll see if I can work around it somehow... I'm not sure how you are building your kernels, but gcc v10 is causing a lot of problems, I would suggest compiling with an earlier gcc for the near future until things get sorted (I'm doing the kernel-secnext builds on stable Fedora, not Rawhide, for now). -- paul moore www.paul-moore.com ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: possible deadlock in sidtab_sid2str_put 2020-01-28 17:29 ` Paul Moore @ 2020-02-03 8:46 ` Ondrej Mosnacek 0 siblings, 0 replies; 11+ messages in thread From: Ondrej Mosnacek @ 2020-02-03 8:46 UTC (permalink / raw) To: Paul Moore Cc: Stephen Smalley, Jeff Vander Stoep, Eric Paris, Jann Horn, Kees Cook, Linux kernel mailing list, Paul E. McKenney, SElinux list, syzkaller-bugs, syzbot On Tue, Jan 28, 2020 at 6:29 PM Paul Moore <paul@paul-moore.com> wrote: > On Tue, Jan 28, 2020 at 11:31 AM Ondrej Mosnacek <omosnace@redhat.com> wrote: > > ... the current rawhide 5.5.0-1 kernel seems to have some bug > > that prevents it from booting on anything with more than one core. > > I'll see if I can work around it somehow... > > I'm not sure how you are building your kernels, but gcc v10 is causing > a lot of problems, I would suggest compiling with an earlier gcc for > the near future until things get sorted (I'm doing the kernel-secnext > builds on stable Fedora, not Rawhide, for now). Right, thanks, I was using the Rawhide buildroot to build the test kernel (derived from Rawhide dist-git source + selinux-next + the patch). Fortunately the Rawhide kernel can be also built against the f31 target without any additional hacks, so I managed to build a an upstream-based kernel with GCC 9 and it didn't have the crash-on-multi-core issue. Regardless, I wasn't able to reproduce the syzbot crash locally, so I had to ask syzbot to test the patch from my git tree [1] and it passed. Nonetheless, I checked to see how the sidtab string cache + IRQ-safe locking (assuming mostly cache hits) compares to the non-cache situation with a category-free label (unconfined_u:unconfined_r:unconfined_t:s0) and the cache (3.2% impact when mostly hits) is still faster than the non-cache version (5.5% impact best case, 65% impact worst case). I intend to incorporate all this information into the log message and then post the patch. [1] https://groups.google.com/d/msg/syzkaller-bugs/1UwATFnIiW8/kOpRrjyNAAAJ -- Ondrej Mosnacek <omosnace at redhat dot com> Software Engineer, Security Technologies Red Hat, Inc. ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: possible deadlock in sidtab_sid2str_put 2020-01-28 13:39 ` Paul Moore 2020-01-28 13:45 ` Stephen Smalley @ 2020-01-28 13:51 ` Ondrej Mosnacek 1 sibling, 0 replies; 11+ messages in thread From: Ondrej Mosnacek @ 2020-01-28 13:51 UTC (permalink / raw) To: Paul Moore Cc: Jeff Vander Stoep, Stephen Smalley, Eric Paris, Jann Horn, Kees Cook, Linux kernel mailing list, Paul E. McKenney, SElinux list, syzkaller-bugs, syzbot On Tue, Jan 28, 2020 at 2:39 PM Paul Moore <paul@paul-moore.com> wrote: > On Tue, Jan 28, 2020 at 7:50 AM syzbot > <syzbot+61cba5033e2072d61806@syzkaller.appspotmail.com> wrote: > > > > syzbot has found a reproducer for the following crash on: > > > > HEAD commit: b0be0eff Merge tag 'x86-pti-2020-01-28' of git://git.kerne.. > > git tree: upstream > > console output: https://syzkaller.appspot.com/x/log.txt?x=1432aebee00000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=9784e57c96a92f20 > > dashboard link: https://syzkaller.appspot.com/bug?extid=61cba5033e2072d61806 > > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10088e95e00000 > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13fa605ee00000 > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > Reported-by: syzbot+61cba5033e2072d61806@syzkaller.appspotmail.com > > > > ===================================================== > > WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected > > 5.5.0-syzkaller #0 Not tainted > > ----------------------------------------------------- > > syz-executor305/10624 [HC0[0]:SC0[2]:HE1:SE0] is trying to acquire: > > ffff888098c14098 (&(&s->cache_lock)->rlock){+.+.}, at: spin_lock include/linux/spinlock.h:338 [inline] > > ffff888098c14098 (&(&s->cache_lock)->rlock){+.+.}, at: sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 > > > > and this task is already holding: > > ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] > > ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 > > which would create a new lock dependency: > > (&(&nf_conntrack_locks[i])->rlock){+.-.} -> (&(&s->cache_lock)->rlock){+.+.} > > > > but this new dependency connects a SOFTIRQ-irq-safe lock: > > (&(&nf_conntrack_locks[i])->rlock){+.-.} > > > > ... which became SOFTIRQ-irq-safe at: > > lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 > > __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] > > _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 > > spin_lock include/linux/spinlock.h:338 [inline] > > nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 > > ... > > > to a SOFTIRQ-irq-unsafe lock: > > (&(&s->cache_lock)->rlock){+.+.} > > > > ... which became SOFTIRQ-irq-unsafe at: > > ... > > lock_acquire+0x190/0x410 kernel/locking/lockdep.c:4484 > > __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline] > > _raw_spin_lock+0x2f/0x40 kernel/locking/spinlock.c:151 > > spin_lock include/linux/spinlock.h:338 [inline] > > sidtab_sid2str_put.part.0+0x36/0x880 security/selinux/ss/sidtab.c:533 > > sidtab_sid2str_put+0xa0/0xc0 security/selinux/ss/sidtab.c:566 > > sidtab_entry_to_string security/selinux/ss/services.c:1279 [inline] > > sidtab_entry_to_string+0xf2/0x110 security/selinux/ss/services.c:1266 > > security_sid_to_context_core+0x2c6/0x3c0 security/selinux/ss/services.c:1361 > > security_sid_to_context+0x34/0x40 security/selinux/ss/services.c:1384 > > avc_audit_post_callback+0x102/0x790 security/selinux/avc.c:709 > > common_lsm_audit+0x5ac/0x1e00 security/lsm_audit.c:466 > > slow_avc_audit+0x16a/0x1f0 security/selinux/avc.c:782 > > avc_audit security/selinux/include/avc.h:140 [inline] > > avc_has_perm+0x543/0x610 security/selinux/avc.c:1185 > > inode_has_perm+0x1a8/0x230 security/selinux/hooks.c:1631 > > selinux_mmap_file+0x10a/0x1d0 security/selinux/hooks.c:3701 > > security_mmap_file+0xa4/0x1e0 security/security.c:1482 > > vm_mmap_pgoff+0xf0/0x230 mm/util.c:502 > > ... > > > other info that might help us debug this: > > > > Possible interrupt unsafe locking scenario: > > > > CPU0 CPU1 > > ---- ---- > > lock(&(&s->cache_lock)->rlock); > > local_irq_disable(); > > lock(&(&nf_conntrack_locks[i])->rlock); > > lock(&(&s->cache_lock)->rlock); > > <Interrupt> > > lock(&(&nf_conntrack_locks[i])->rlock); > > > > *** DEADLOCK *** > > > > 4 locks held by syz-executor305/10624: > > #0: ffffffff8c1acc68 (&table[i].mutex){+.+.}, at: nfnl_lock net/netfilter/nfnetlink.c:62 [inline] > > #0: ffffffff8c1acc68 (&table[i].mutex){+.+.}, at: nfnetlink_rcv_msg+0x9ee/0xfb0 net/netfilter/nfnetlink.c:224 > > #1: ffff8880836415d8 (nlk_cb_mutex-NETFILTER){+.+.}, at: netlink_dump+0xe7/0xfb0 net/netlink/af_netlink.c:2199 > > #2: ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: spin_lock include/linux/spinlock.h:338 [inline] > > #2: ffffffff89865770 (&(&nf_conntrack_locks[i])->rlock){+.-.}, at: nf_conntrack_lock+0x17/0x70 net/netfilter/nf_conntrack_core.c:91 > > #3: ffffffff8b7df008 (&selinux_ss.policy_rwlock){.+.?}, at: security_sid_to_context_core+0x1ca/0x3c0 security/selinux/ss/services.c:1344 > > I think this is going to be tricky to fix due to the differing > contexts from which sidtab_sid2str_put() may be called. We already > have a check for !in_task() in sidtab_sid2str_put(), do we want to add > a check for !in_serving_softirq() too? I don't think that is going to fix it. The issue here is that an interrupt may happen while we are holding the lock and in that interrupt we try to take some other lock, which another thread has taken before the cache lock... I'm afraid using the irqsave/irqrestore locking is the only possible fix here... (Either that or giving up on the proper least-recently-used logic.) -- Ondrej Mosnacek <omosnace at redhat dot com> Software Engineer, Security Technologies Red Hat, Inc. ^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: possible deadlock in sidtab_sid2str_put 2020-01-28 4:27 possible deadlock in sidtab_sid2str_put syzbot 2020-01-28 12:50 ` syzbot @ 2020-01-28 15:28 ` syzbot 1 sibling, 0 replies; 11+ messages in thread From: syzbot @ 2020-01-28 15:28 UTC (permalink / raw) To: eparis, jannh, jeffv, keescook, linux-kernel, omosnace, paul, paulmck, sds, selinux, syzkaller-bugs syzbot has bisected this bug to: commit d97bd23c2d7d866e99eb3a927c742715c85a90ef Author: Ondrej Mosnacek <omosnace@redhat.com> Date: Tue Nov 26 13:57:00 2019 +0000 selinux: cache the SID -> context string translation bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13fe5f69e00000 start commit: b0be0eff Merge tag 'x86-pti-2020-01-28' of git://git.kerne.. git tree: upstream final crash: https://syzkaller.appspot.com/x/report.txt?x=10015f69e00000 console output: https://syzkaller.appspot.com/x/log.txt?x=17fe5f69e00000 kernel config: https://syzkaller.appspot.com/x/.config?x=9784e57c96a92f20 dashboard link: https://syzkaller.appspot.com/bug?extid=61cba5033e2072d61806 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10088e95e00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13fa605ee00000 Reported-by: syzbot+61cba5033e2072d61806@syzkaller.appspotmail.com Fixes: d97bd23c2d7d ("selinux: cache the SID -> context string translation") For information about bisection process see: https://goo.gl/tpsmEJ#bisection ^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2020-02-03 8:47 UTC | newest] Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2020-01-28 4:27 possible deadlock in sidtab_sid2str_put syzbot 2020-01-28 12:50 ` syzbot 2020-01-28 13:39 ` Paul Moore 2020-01-28 13:45 ` Stephen Smalley 2020-01-28 14:26 ` Ondrej Mosnacek 2020-01-28 15:45 ` Paul Moore 2020-01-28 16:30 ` Ondrej Mosnacek 2020-01-28 17:29 ` Paul Moore 2020-02-03 8:46 ` Ondrej Mosnacek 2020-01-28 13:51 ` Ondrej Mosnacek 2020-01-28 15:28 ` syzbot
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