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* KASAN: use-after-free Read in addr_handler (2)
@ 2020-06-10 17:02 syzbot
       [not found] ` <>
  0 siblings, 1 reply; 8+ messages in thread
From: syzbot @ 2020-06-10 17:02 UTC (permalink / raw)
  To: chuck.lever, dledford, jgg, leon, linux-kernel, linux-rdma,
	parav, syzkaller-bugs


syzbot found the following crash on:

HEAD commit:    7ae77150 Merge tag 'powerpc-5.8-1' of git://
git tree:       upstream
console output:
kernel config:
dashboard link:
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:

BUG: KASAN: use-after-free in __mutex_lock_common kernel/locking/mutex.c:938 [inline]
BUG: KASAN: use-after-free in __mutex_lock+0x1033/0x13c0 kernel/locking/mutex.c:1103
Read of size 8 at addr ffff888088ec33b0 by task kworker/u4:5/14014

CPU: 1 PID: 14014 Comm: kworker/u4:5 Not tainted 5.7.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: ib_addr process_one_req
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x188/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd3/0x413 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 __mutex_lock_common kernel/locking/mutex.c:938 [inline]
 __mutex_lock+0x1033/0x13c0 kernel/locking/mutex.c:1103
 addr_handler+0xa0/0x340 drivers/infiniband/core/cma.c:3100
 process_one_req+0xfa/0x680 drivers/infiniband/core/addr.c:643
 process_one_work+0x965/0x16a0 kernel/workqueue.c:2268
 worker_thread+0x96/0xe20 kernel/workqueue.c:2414
 kthread+0x388/0x470 kernel/kthread.c:268
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351

Allocated by task 31499:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc mm/kasan/common.c:494 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:467
 kmem_cache_alloc_trace+0x153/0x7d0 mm/slab.c:3551
 kmalloc include/linux/slab.h:555 [inline]
 kzalloc include/linux/slab.h:669 [inline]
 __rdma_create_id+0x5b/0x850 drivers/infiniband/core/cma.c:861
 ucma_create_id+0x1d1/0x590 drivers/infiniband/core/ucma.c:503
 ucma_write+0x285/0x350 drivers/infiniband/core/ucma.c:1729
 __vfs_write+0x76/0x100 fs/read_write.c:495
 vfs_write+0x268/0x5d0 fs/read_write.c:559
 ksys_write+0x1ee/0x250 fs/read_write.c:612
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295

Freed by task 31496:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x109/0x2b0 mm/slab.c:3757
 ucma_close+0x111/0x300 drivers/infiniband/core/ucma.c:1807
 __fput+0x33e/0x880 fs/file_table.c:281
 task_work_run+0xf4/0x1b0 kernel/task_work.c:123
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x2fa/0x360 arch/x86/entry/common.c:165
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:279 [inline]
 do_syscall_64+0x6b1/0x7d0 arch/x86/entry/common.c:305

The buggy address belongs to the object at ffff888088ec3000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 944 bytes inside of
 2048-byte region [ffff888088ec3000, ffff888088ec3800)
The buggy address belongs to the page:
page:ffffea000223b0c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea000299f588 ffffea000263d0c8 ffff8880aa000e00
raw: 0000000000000000 ffff888088ec3000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888088ec3280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888088ec3300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888088ec3380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888088ec3400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888088ec3480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

This bug is generated by a bot. It may contain errors.
See for more information about syzbot.
syzbot engineers can be reached at

syzbot will keep track of this bug report. See: for how to communicate with syzbot.

^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2020-06-29 19:42 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-06-10 17:02 KASAN: use-after-free Read in addr_handler (2) syzbot
     [not found] ` <>
2020-06-27  0:45   ` Jason Gunthorpe
2020-06-27  2:38     ` [PATCH] RDMA/cma: Execute rdma_cm destruction from a handler properly kernel test robot
     [not found]   ` <>
2020-06-27 22:25     ` KASAN: use-after-free Read in addr_handler (2) Jason Gunthorpe
2020-06-29 14:42       ` Dmitry Vyukov
2020-06-29 17:27         ` Dmitry Vyukov
2020-06-29 19:22           ` Jason Gunthorpe
2020-06-29 19:41             ` Dmitry Vyukov

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