BUG: corrupted list in unlink_anon_vmas

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: d15be546 Merge tag 'media/v5.8-3' of git://git.kernel.org/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=10954ac8900000
kernel config: https://syzkaller.appspot.com/x/.config?x=f87a5e4232fdb267
dashboard link: https://syzkaller.appspot.com/bug?extid=c6717a67be2e8c701b76
compiler: gcc (GCC) 10.1.0-syz 20200507
userspace arch: i386
CC: [ak...@linux-foundation.org linux-...@vger.kernel.org linu...@kvack.org]

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c6717a...@syzkaller.appspotmail.com

list_del corruption. next->prev should be ffff8880375f4c50, but was 0000000000000000
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:54!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 25866 Comm: syz-executor.2 Not tainted 5.8.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__list_del_entry_valid.cold+0x48/0x55 lib/list_debug.c:54
Code: e8 31 fd c1 fd 0f 0b 4c 89 e2 48 89 ee 48 c7 c7 e0 93 93 88 e8 1d fd c1 fd 0f 0b 48 89 ee 48 c7 c7 a0 94 93 88 e8 0c fd c1 fd <0f> 0b cc cc cc cc cc cc cc cc cc cc cc 41 57 41 56 41 55 41 54 55
RSP: 0018:ffffc900160f7b90 EFLAGS: 00010282
RAX: 0000000000000054 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: ffff8880a01e2300 RSI: ffffffff815d4eb7 RDI: fffff52002c1ef64
RBP: ffff8880375f4c50 R08: 0000000000000054 R09: ffff8880ae7318e7
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88802cd1b9b0
R13: ffff8880008907f0 R14: ffff8880a1aa0400 R15: ffff8880375f4c50
FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000085a0000 CR3: 0000000094bc6000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
__list_del_entry include/linux/list.h:132 [inline]
list_del include/linux/list.h:146 [inline]
unlink_anon_vmas+0xa3/0x830 mm/rmap.c:413
free_pgtables+0x1ab/0x2f0 mm/memory.c:412
exit_mmap+0x2c0/0x510 mm/mmap.c:3151
__mmput+0x122/0x470 kernel/fork.c:1093
mmput+0x53/0x60 kernel/fork.c:1114
exit_mm kernel/exit.c:482 [inline]
do_exit+0xa8f/0x2a40 kernel/exit.c:792
do_group_exit+0x125/0x310 kernel/exit.c:903
__do_sys_exit_group kernel/exit.c:914 [inline]
__se_sys_exit_group kernel/exit.c:912 [inline]
__ia32_sys_exit_group+0x3a/0x50 kernel/exit.c:912
do_syscall_32_irqs_on+0x3f/0x60 arch/x86/entry/common.c:428
__do_fast_syscall_32 arch/x86/entry/common.c:475 [inline]
do_fast_syscall_32+0x7f/0x120 arch/x86/entry/common.c:503
entry_SYSENTER_compat_after_hwframe+0x4d/0x5c
RIP: 0023:0xf7fb1569
Code: Bad RIP value.
RSP: 002b:00000000086afd7c EFLAGS: 00000202 ORIG_RAX: 00000000000000fc
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000080acac5
RDX: 0000000000000001 RSI: 000000000000001e RDI: 00000000081a0008
RBP: 000000000805a78b R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Modules linked in:
---[ end trace 3aae26f601fdf313 ]---
RIP: 0010:__list_del_entry_valid.cold+0x48/0x55 lib/list_debug.c:54
Code: e8 31 fd c1 fd 0f 0b 4c 89 e2 48 89 ee 48 c7 c7 e0 93 93 88 e8 1d fd c1 fd 0f 0b 48 89 ee 48 c7 c7 a0 94 93 88 e8 0c fd c1 fd <0f> 0b cc cc cc cc cc cc cc cc cc cc cc 41 57 41 56 41 55 41 54 55
RSP: 0018:ffffc900160f7b90 EFLAGS: 00010282
RAX: 0000000000000054 RBX: dffffc0000000000 RCX: 0000000000000000
RDX: ffff8880a01e2300 RSI: ffffffff815d4eb7 RDI: fffff52002c1ef64
RBP: ffff8880375f4c50 R08: 0000000000000054 R09: ffff8880ae7318e7
R10: 0000000000000000 R11: 0000000000000000 R12: ffff88802cd1b9b0
R13: ffff8880008907f0 R14: ffff8880a1aa0400 R15: ffff8880375f4c50
FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS: 0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 000000000000000e CR3: 0000000009a79000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.