On Sat, 04 Dec 2021 01:55:17 -0800 syzbot <syzbot+7cd473c2cac13fd2dd72@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 58e1100fdc59 MAINTAINERS: co-maintain random.c > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=1362881eb00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=e9ea28d2c3c2c389 > dashboard link: https://syzkaller.appspot.com/bug?extid=7cd473c2cac13fd2dd72 > compiler: Debian clang version 11.0.1-2, GNU ld (GNU Binutils for Debian) 2.35.2 > > 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+7cd473c2cac13fd2dd72@xxxxxxxxxxxxxxxxxxxxxxxxx > > BUG: kernel NULL pointer dereference, address: 0000000000000000 cc linux-f2fs-devel@xxxxxxxxxxxxxxxxxxxxx And willy, who might help with diagnosing this. But it does seem that f2fs got itself a NULL page* then put it in places where it shouldn't have. > #PF: supervisor instruction fetch in kernel mode > #PF: error_code(0x0010) - not-present page > PGD 70764067 P4D 70764067 PUD 0 > Oops: 0010 [#1] PREEMPT SMP KASAN > CPU: 1 PID: 6541 Comm: syz-executor.3 Not tainted 5.16.0-rc3-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > RIP: 0010:0x0 > Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. > RSP: 0018:ffffc900027ff7f8 EFLAGS: 00010246 > RAX: 1ffffffff14fef03 RBX: ffffffff8a7f7818 RCX: ffff88801b40d700 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea0002790ec0 > RBP: dffffc0000000000 R08: ffffffff81b0fa16 R09: fffff940004f21d9 > R10: fffff940004f21d9 R11: 0000000000000000 R12: ffff88806c11c7b0 > R13: 0000000000000000 R14: 1ffffd40004f21d9 R15: ffffea0002790ec0 > FS: 0000555557165400(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffffffffffffffd6 CR3: 0000000030d85000 CR4: 00000000003526e0 > Call Trace: > <TASK> > folio_mark_dirty+0x136/0x270 mm/page-writeback.c:2639 > f2fs_update_meta_page+0x4b/0x380 fs/f2fs/segment.c:2485 > do_checkpoint fs/f2fs/checkpoint.c:1513 [inline] > f2fs_write_checkpoint+0x31ad/0x5430 fs/f2fs/checkpoint.c:1674 > f2fs_issue_checkpoint+0x361/0x4e0 > sync_filesystem+0x19c/0x1f0 fs/sync.c:63 > generic_shutdown_super+0x6b/0x300 fs/super.c:448 > kill_block_super+0x79/0xd0 fs/super.c:1397 > kill_f2fs_super+0x2f9/0x3c0 fs/f2fs/super.c:4478 > deactivate_locked_super+0xa7/0xf0 fs/super.c:335 > cleanup_mnt+0x462/0x510 fs/namespace.c:1137 > task_work_run+0x146/0x1c0 kernel/task_work.c:164 > tracehook_notify_resume include/linux/tracehook.h:189 [inline] > exit_to_user_mode_loop kernel/entry/common.c:175 [inline] > exit_to_user_mode_prepare+0x209/0x220 kernel/entry/common.c:207 > __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline] > syscall_exit_to_user_mode+0x2e/0x70 kernel/entry/common.c:300 > do_syscall_64+0x53/0xd0 arch/x86/entry/common.c:86 > entry_SYSCALL_64_after_hwframe+0x44/0xae > RIP: 0033:0x7f6cfdd59f57 > Code: ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 31 f6 e9 09 00 00 00 66 0f 1f 84 00 00 00 00 00 b8 a6 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007fffcbddcad8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 > RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00007f6cfdd59f57 > RDX: 00007fffcbddcbac RSI: 000000000000000a RDI: 00007fffcbddcba0 > RBP: 00007fffcbddcba0 R08: 00000000ffffffff R09: 00007fffcbddc970 > R10: 0000555557166903 R11: 0000000000000246 R12: 00007f6cfddb2105 > R13: 00007fffcbdddc60 R14: 0000555557166810 R15: 00007fffcbdddca0 > </TASK> > Modules linked in: > CR2: 0000000000000000 > ---[ end trace 08eda5a5e35b48a0 ]--- > RIP: 0010:0x0 > Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6. > RSP: 0018:ffffc900027ff7f8 EFLAGS: 00010246 > RAX: 1ffffffff14fef03 RBX: ffffffff8a7f7818 RCX: ffff88801b40d700 > RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea0002790ec0 > RBP: dffffc0000000000 R08: ffffffff81b0fa16 R09: fffff940004f21d9 > R10: fffff940004f21d9 R11: 0000000000000000 R12: ffff88806c11c7b0 > R13: 0000000000000000 R14: 1ffffd40004f21d9 R15: ffffea0002790ec0 > FS: 0000555557165400(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffffffffffffffd6 CR3: 0000000030d85000 CR4: 00000000003526e0 > > > --- > 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.
