Hello, syzbot found the following issue on: HEAD commit: 28806e4d Merge tag 'media/v5.12-2' of git://git.kernel.org.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=136d1bbcd00000 kernel config: https://syzkaller.appspot.com/x/.config?x=6bcf96204c1b8e77 dashboard link: https://syzkaller.appspot.com/bug?extid=628472a2aac693ab0fcd syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1133abfad00000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1191aab2d00000 The issue was bisected to: commit 2d01ddc86606564fb08c56e3bc93a0693895f710 Author: Jan Kara <jack@xxxxxxx> Date: Wed Dec 16 10:18:40 2020 +0000 ext4: save error info to sb through journal if available bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=152b9d56d00000 final oops: https://syzkaller.appspot.com/x/report.txt?x=172b9d56d00000 console output: https://syzkaller.appspot.com/x/log.txt?x=132b9d56d00000 IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+628472a2aac693ab0fcd@xxxxxxxxxxxxxxxxxxxxxxxxx Fixes: 2d01ddc86606 ("ext4: save error info to sb through journal if available") ODEBUG: free active (active state 0) object type: timer_list hint: print_daily_error_info+0x0/0x1f0 fs/ext4/super.c:1334 WARNING: CPU: 1 PID: 12723 at lib/debugobjects.c:505 debug_print_object+0x16e/0x250 lib/debugobjects.c:505 Modules linked in: CPU: 0 PID: 12723 Comm: syz-executor932 Not tainted 5.12.0-rc2-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:debug_print_object+0x16e/0x250 lib/debugobjects.c:505 Code: ff df 48 89 fa 48 c1 ea 03 80 3c 02 00 0f 85 af 00 00 00 48 8b 14 dd a0 06 c2 89 4c 89 ee 48 c7 c7 a0 fa c1 89 e8 fc 41 f8 04 <0f> 0b 83 05 05 7e fb 09 01 48 83 c4 18 5b 5d 41 5c 41 5d 41 5e c3 RSP: 0018:ffffc9000e6ef980 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000000 RDX: ffff88801d5e9bc0 RSI: ffffffff815c0d25 RDI: fffff52001cddf22 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: ffffffff815b9abe R11: 0000000000000000 R12: ffffffff896d7da0 R13: ffffffff89c200e0 R14: ffffffff81629d00 R15: dffffc0000000000 FS: 0000000000f93300(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcda3ec0000 CR3: 00000000155a1000 CR4: 0000000000350ef0 Call Trace: __debug_check_no_obj_freed lib/debugobjects.c:987 [inline] debug_check_no_obj_freed+0x301/0x420 lib/debugobjects.c:1018 slab_free_hook mm/slub.c:1554 [inline] slab_free_freelist_hook+0x147/0x210 mm/slub.c:1600 slab_free mm/slub.c:3161 [inline] kfree+0xe5/0x7f0 mm/slub.c:4213 ext4_fill_super+0x84f/0xded0 fs/ext4/super.c:5182 mount_bdev+0x34d/0x410 fs/super.c:1367 legacy_get_tree+0x105/0x220 fs/fs_context.c:592 vfs_get_tree+0x89/0x2f0 fs/super.c:1497 do_new_mount fs/namespace.c:2903 [inline] path_mount+0x132a/0x1f90 fs/namespace.c:3233 do_mount fs/namespace.c:3246 [inline] __do_sys_mount fs/namespace.c:3454 [inline] __se_sys_mount fs/namespace.c:3431 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3431 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x445c0a Code: 48 c7 c2 c0 ff ff ff f7 d8 64 89 02 b8 ff ff ff ff eb d2 e8 a8 00 00 00 0f 1f 84 00 00 00 00 00 49 89 ca b8 a5 00 00 00 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:00007ffe8bf4c3b8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007ffe8bf4c410 RCX: 0000000000445c0a RDX: 0000000020000040 RSI: 0000000020000100 RDI: 00007ffe8bf4c3d0 RBP: 00007ffe8bf4c3d0 R08: 00007ffe8bf4c410 R09: 0000000000000000 --- This report 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@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. For information about bisection process see: https://goo.gl/tpsmEJ#bisection syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches