[syzbot] KASAN: stack-out-of-bounds Read in xfs_buf_delwri_submit_buffers

From: syzbot <syzbot+d2cdeba65d32ed1d2c4d@syzkaller.appspotmail.com>
To: djwong@kernel.org, linux-kernel@vger.kernel.org,
	linux-xfs@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: [syzbot] KASAN: stack-out-of-bounds Read in xfs_buf_delwri_submit_buffers
Date: Sun, 11 Dec 2022 23:01:54 -0800	[thread overview]
Message-ID: <00000000000019e05005ef9c1481@google.com> (raw)

Hello,

syzbot found the following issue on:

HEAD commit:    3ecc37918c80 Merge tag 'media/v6.1-4' of git://git.kernel...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=162de243880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d58e7fe7f9cf5e24
dashboard link: https://syzkaller.appspot.com/bug?extid=d2cdeba65d32ed1d2c4d
compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=170a950b880000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1625948f880000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/be14794fd26b/disk-3ecc3791.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/35b850996388/vmlinux-3ecc3791.xz
kernel image: https://storage.googleapis.com/syzbot-assets/0eec0f8f6777/bzImage-3ecc3791.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/f72864a73792/mount_0.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d2cdeba65d32ed1d2c4d@syzkaller.appspotmail.com

XFS (loop5): Quotacheck: Done.
==================================================================
BUG: KASAN: stack-out-of-bounds in __lock_acquire+0x79/0x1f60 kernel/locking/lockdep.c:4925
Read of size 8 at addr ffffc9000cad7918 by task syz-executor223/5006

CPU: 1 PID: 5006 Comm: syz-executor223 Not tainted 6.1.0-rc8-syzkaller-00152-g3ecc37918c80 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
 print_address_description+0x74/0x340 mm/kasan/report.c:284
 print_report+0x107/0x1f0 mm/kasan/report.c:395
 kasan_report+0xcd/0x100 mm/kasan/report.c:495
 __lock_acquire+0x79/0x1f60 kernel/locking/lockdep.c:4925
 lock_acquire+0x182/0x3c0 kernel/locking/lockdep.c:5668
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xb3/0x100 kernel/locking/spinlock.c:162
 down+0x35/0xb0 kernel/locking/semaphore.c:59
 xfs_buf_lock fs/xfs/xfs_buf.c:1120 [inline]
 xfs_buf_delwri_submit_buffers+0x22e/0x820 fs/xfs/xfs_buf.c:2164
 xfs_buf_delwri_submit+0xbb/0x320 fs/xfs/xfs_buf.c:2242
 xfs_qm_shrink_scan+0x1ca/0x410 fs/xfs/xfs_qm.c:514
 do_shrink_slab+0x4e1/0xa00 mm/vmscan.c:842
 shrink_slab+0x1e6/0x340 mm/vmscan.c:1002
 drop_slab_node mm/vmscan.c:1037 [inline]
 drop_slab+0x185/0x2c0 mm/vmscan.c:1047
 drop_caches_sysctl_handler+0xb1/0x160 fs/drop_caches.c:66
 proc_sys_call_handler+0x576/0x890 fs/proc/proc_sysctl.c:604
 do_iter_write+0x6c2/0xc20 fs/read_write.c:861
 iter_file_splice_write+0x7fc/0xfc0 fs/splice.c:686
 do_splice_from fs/splice.c:764 [inline]
 direct_splice_actor+0xe6/0x1c0 fs/splice.c:931
 splice_direct_to_actor+0x4e4/0xc00 fs/splice.c:886
 do_splice_direct+0x279/0x3d0 fs/splice.c:974
 do_sendfile+0x5fb/0xf80 fs/read_write.c:1255
 __do_sys_sendfile64 fs/read_write.c:1317 [inline]
 __se_sys_sendfile64+0xd0/0x1b0 fs/read_write.c:1309
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fb176007db9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 31 18 00 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff863d4df8 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 0000000000055e8c RCX: 00007fb176007db9
RDX: 0000000020002080 RSI: 0000000000000004 RDI: 0000000000000005
RBP: 0000000000000000 R08: 00007fff863d4e20 R09: 00007fff863d4e20
R10: 0000000000000870 R11: 0000000000000246 R12: 00007fff863d4e1c
R13: 00007fff863d4e50 R14: 00007fff863d4e30 R15: 000000000000001a
 </TASK>

The buggy address belongs to the virtual mapping at
 [ffffc9000cad0000, ffffc9000cad9000) created by:
 dup_task_struct+0x8b/0x490 kernel/fork.c:974

The buggy address belongs to the physical page:
page:ffffea0001dbf580 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x76fd6
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x2dc2(GFP_KERNEL|__GFP_HIGHMEM|__GFP_NOWARN|__GFP_ZERO), pid 2, tgid 2 (kthreadd), ts 350542932176, free_ts 350448019466
 prep_new_page mm/page_alloc.c:2539 [inline]
 get_page_from_freelist+0x742/0x7c0 mm/page_alloc.c:4291
 __alloc_pages+0x259/0x560 mm/page_alloc.c:5558
 vm_area_alloc_pages mm/vmalloc.c:2975 [inline]
 __vmalloc_area_node mm/vmalloc.c:3043 [inline]
 __vmalloc_node_range+0x9b2/0x1400 mm/vmalloc.c:3213
 alloc_thread_stack_node+0x307/0x500 kernel/fork.c:311
 dup_task_struct+0x8b/0x490 kernel/fork.c:974
 copy_process+0x637/0x4000 kernel/fork.c:2084
 kernel_clone+0x21b/0x620 kernel/fork.c:2671
 kernel_thread+0x150/0x1d0 kernel/fork.c:2731
 create_kthread kernel/kthread.c:399 [inline]
 kthreadd+0x57c/0x750 kernel/kthread.c:746
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1459 [inline]
 free_pcp_prepare+0x80c/0x8f0 mm/page_alloc.c:1509
 free_unref_page_prepare mm/page_alloc.c:3387 [inline]
 free_unref_page_list+0xb4/0x7b0 mm/page_alloc.c:3529
 release_pages+0x232a/0x25c0 mm/swap.c:1055
 __pagevec_release+0x7d/0xf0 mm/swap.c:1075
 pagevec_release include/linux/pagevec.h:71 [inline]
 folio_batch_release include/linux/pagevec.h:135 [inline]
 truncate_inode_pages_range+0x472/0x17f0 mm/truncate.c:373
 kill_bdev block/bdev.c:76 [inline]
 blkdev_flush_mapping+0x153/0x2c0 block/bdev.c:662
 blkdev_put_whole block/bdev.c:693 [inline]
 blkdev_put+0x4a5/0x730 block/bdev.c:953
 deactivate_locked_super+0xa7/0xf0 fs/super.c:332
 cleanup_mnt+0x494/0x520 fs/namespace.c:1186
 task_work_run+0x243/0x300 kernel/task_work.c:179
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0x124/0x150 kernel/entry/common.c:171
 exit_to_user_mode_prepare+0xb2/0x140 kernel/entry/common.c:203
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x26/0x60 kernel/entry/common.c:296
 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffffc9000cad7800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffffc9000cad7880: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffffc9000cad7900: f3 f3 f3 f3 f3 f3 f3 f3 00 00 00 00 00 00 00 00
                            ^
 ffffc9000cad7980: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1
 ffffc9000cad7a00: 00 00 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

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