Hello, syzbot found the following issue on: HEAD commit: 6d36c728bc2e Merge tag 'net-6.1-rc2' of git://git.kernel.o.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1526d2e2880000 kernel config: https://syzkaller.appspot.com/x/.config?x=afc317c0f52ce670 dashboard link: https://syzkaller.appspot.com/bug?extid=53369d11851d8f26735c compiler: Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/a2030ff47985/disk-6d36c728.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/82a6ec6fd4db/vmlinux-6d36c728.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+53369d11851d8f26735c@xxxxxxxxxxxxxxxxxxxxxxxxx NILFS (loop4): discard dirty block: blocknr=0, size=1024 NILFS (loop4): discard dirty block: blocknr=0, size=1024 NILFS (loop4): discard dirty block: blocknr=0, size=1024 NILFS (loop4): discard dirty block: blocknr=0, size=1024 general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 1 PID: 5633 Comm: kworker/u4:11 Not tainted 6.1.0-rc1-syzkaller-00093-g6d36c728bc2e #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/11/2022 Workqueue: writeback wb_workfn (flush-7:4) RIP: 0010:nilfs_clear_dirty_page+0x9a/0x1080 fs/nilfs2/page.c:387 Code: 31 e8 9a b3 3c fe 49 8d 5f 18 48 89 d8 48 c1 e8 03 42 80 3c 30 00 74 08 48 89 df e8 e0 9c 90 fe 48 8b 1b 48 89 d8 48 c1 e8 03 <42> 80 3c 30 00 74 08 48 89 df e8 c7 9c 90 fe 4c 8b 2b 49 8d 5d 28 RSP: 0018:ffffc900053e7020 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff888026a08000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea00020d3440 RBP: ffffc900053e70f0 R08: ffffffff834ae92a R09: fffff9400041a689 R10: fffff9400041a689 R11: 1ffffd400041a688 R12: 000000000000000e R13: 0000000000000000 R14: dffffc0000000000 R15: ffffea00020d3440 FS: 0000000000000000(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f592433f000 CR3: 0000000033285000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> nilfs_clear_dirty_pages+0x1d9/0x380 fs/nilfs2/page.c:372 nilfs_writepages+0x117/0x150 fs/nilfs2/inode.c:165 do_writepages+0x3c3/0x680 mm/page-writeback.c:2469 __writeback_single_inode+0xd1/0x670 fs/fs-writeback.c:1587 writeback_sb_inodes+0xb3b/0x18f0 fs/fs-writeback.c:1870 __writeback_inodes_wb+0x125/0x420 fs/fs-writeback.c:1941 wb_writeback+0x440/0x7b0 fs/fs-writeback.c:2046 wb_check_start_all fs/fs-writeback.c:2168 [inline] wb_do_writeback fs/fs-writeback.c:2194 [inline] wb_workfn+0x827/0xef0 fs/fs-writeback.c:2227 process_one_work+0x877/0xdb0 kernel/workqueue.c:2289 worker_thread+0xb14/0x1330 kernel/workqueue.c:2436 kthread+0x266/0x300 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 </TASK> Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:nilfs_clear_dirty_page+0x9a/0x1080 fs/nilfs2/page.c:387 Code: 31 e8 9a b3 3c fe 49 8d 5f 18 48 89 d8 48 c1 e8 03 42 80 3c 30 00 74 08 48 89 df e8 e0 9c 90 fe 48 8b 1b 48 89 d8 48 c1 e8 03 <42> 80 3c 30 00 74 08 48 89 df e8 c7 9c 90 fe 4c 8b 2b 49 8d 5d 28 RSP: 0018:ffffc900053e7020 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff888026a08000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffea00020d3440 RBP: ffffc900053e70f0 R08: ffffffff834ae92a R09: fffff9400041a689 R10: fffff9400041a689 R11: 1ffffd400041a688 R12: 000000000000000e R13: 0000000000000000 R14: dffffc0000000000 R15: ffffea00020d3440 FS: 0000000000000000(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c000074368 CR3: 000000007ef36000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 ---------------- Code disassembly (best guess), 1 bytes skipped: 0: e8 9a b3 3c fe callq 0xfe3cb39f 5: 49 8d 5f 18 lea 0x18(%r15),%rbx 9: 48 89 d8 mov %rbx,%rax c: 48 c1 e8 03 shr $0x3,%rax 10: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1) 15: 74 08 je 0x1f 17: 48 89 df mov %rbx,%rdi 1a: e8 e0 9c 90 fe callq 0xfe909cff 1f: 48 8b 1b mov (%rbx),%rbx 22: 48 89 d8 mov %rbx,%rax 25: 48 c1 e8 03 shr $0x3,%rax * 29: 42 80 3c 30 00 cmpb $0x0,(%rax,%r14,1) <-- trapping instruction 2e: 74 08 je 0x38 30: 48 89 df mov %rbx,%rdi 33: e8 c7 9c 90 fe callq 0xfe909cff 38: 4c 8b 2b mov (%rbx),%r13 3b: 49 8d 5d 28 lea 0x28(%r13),%rbx --- This report is generated by a bot. 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