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WARNING in inc_nlink

Status: upstream: reported C repro on 2023/03/20 05:26
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+642f43b47421d18b19dc@syzkaller.appspotmail.com
First crash: 396d, last: 1d04h
Fix commit to backport (bisect log) :
tree: upstream
commit 97f044f690bac2b094bfb7fb2d177ef946c85880
Author: Miklos Szeredi <mszeredi@redhat.com>
Date: Fri Oct 22 15:03:02 2021 +0000

  fuse: don't increment nlink in link()

  
Fix bisection: the issue occurs on the latest tested release (bisect log)
Crash: WARNING in inc_nlink (log)
Repro: C syz .config
  
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2023/05/14 linux-5.15.y (ToT) b0ece631f84a C [report] WARNING in inc_nlink
2023/05/13 upstream (ToT) d4d58949a6ea C Didn't crash
▶ ▼ Similar bugs (9)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 WARNING in inc_nlink (2) C error 102 509d 1264d 0/1 upstream: reported C repro on 2020/11/01 15:25
upstream WARNING in inc_nlink (2) fs C inconclusive done 21 773d 1109d 20/26 fixed on 2022/03/08 16:11
upstream WARNING in inc_nlink (3) jfs C error error 622 11h44m 763d 0/26 upstream: reported C repro on 2022/03/17 16:37
linux-6.1 WARNING in inc_nlink 81 352d 375d 0/3 auto-obsoleted due to no activity on 2023/07/31 15:23
linux-4.19 WARNING in inc_nlink C done 8 1339d 1487d 1/1 fixed on 2020/09/18 07:23
linux-4.14 WARNING in inc_nlink C done 21 1346d 1488d 1/1 fixed on 2020/09/11 09:49
linux-4.14 WARNING in inc_nlink (2) C 47 424d 1259d 0/1 upstream: reported C repro on 2020/11/06 09:55
upstream WARNING in inc_nlink C done 26 1376d 1479d 15/26 fixed on 2020/09/16 22:51
linux-6.1 WARNING in inc_nlink (2) origin:upstream C 6 3d10h 112d 0/3 upstream: reported C repro on 2023/12/28 21:17
▶ ▼ Fix bisection attempts (7)
Created Duration User Patch Repo Result
2023/12/06 06:14 4h29m fix candidate upstream job log (1)
2023/11/30 14:32 2h14m bisect fix linux-5.15.y job log (0) log
2023/10/30 05:59 1h16m bisect fix linux-5.15.y job log (0) log
2023/09/28 07:46 49m bisect fix linux-5.15.y job log (0) log
2023/07/26 19:45 1h39m bisect fix linux-5.15.y job log (0) log
2023/06/13 07:26 31m bisect fix linux-5.15.y job log (0) log
2023/04/19 09:00 34m bisect fix linux-5.15.y job log (0) log

Sample crash report:
------------[ cut here ]------------
WARNING: CPU: 1 PID: 3499 at fs/inode.c:364 inc_nlink+0x120/0x130
Modules linked in:
CPU: 1 PID: 3499 Comm: syz-executor324 Not tainted 5.15.110-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
RIP: 0010:inc_nlink+0x120/0x130 fs/inode.c:364
Code: ed ff e9 37 ff ff ff 44 89 e9 80 e1 07 80 c1 03 38 c1 0f 8c 49 ff ff ff 4c 89 ef e8 8a ae ed ff e9 3c ff ff ff e8 60 54 a4 ff <0f> 0b eb 80 66 2e 0f 1f 84 00 00 00 00 00 66 90 41 57 41 56 53 48
RSP: 0018:ffffc90002cdfb88 EFLAGS: 00010293
RAX: ffffffff81db8a20 RBX: 1ffff1100e82c0e1 RCX: ffff888015fdba00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: ffffffff81db899a R09: ffffed1003b46158
R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000
R13: ffff888074160708 R14: ffff8880741606c0 R15: 0000000000000000
FS:  00007effafc33700(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001140 CR3: 00000000704d4000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 fuse_link+0x370/0x5b0 fs/fuse/dir.c:944
 vfs_link+0x65e/0x810 fs/namei.c:4486
 do_linkat+0x5c8/0x9d0 fs/namei.c:4557
 __do_sys_link fs/namei.c:4591 [inline]
 __se_sys_link fs/namei.c:4589 [inline]
 __x64_sys_link+0x82/0x90 fs/namei.c:4589
 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+0x61/0xcb
RIP: 0033:0x7effafc81b79
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 81 14 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007effafc332f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000056
RAX: ffffffffffffffda RBX: 00007effafd124c0 RCX: 00007effafc81b79
RDX: 00007effafc81b79 RSI: 0000000020000080 RDI: 0000000020000040
RBP: 00007effafce00e4 R08: 0000000000003065 R09: 0000000000000000
R10: 0000000000003065 R11: 0000000000000246 R12: 00007effafcda0d0
R13: 00007effafcdc0d8 R14: 00007effafcde0e0 R15: 00007effafd124c8
 </TASK>

Crashes (11):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/05/08 08:00 linux-5.15.y 8a7f2a5c5aa1 90c93c40 .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in inc_nlink
2023/03/20 05:50 linux-5.15.y 8020ae3c051d 7939252e .config console log report syz C [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in inc_nlink
2024/04/18 02:59 linux-5.15.y c52b9710c83d acc528cb .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in inc_nlink
2023/03/20 05:26 linux-5.15.y 8020ae3c051d 7939252e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan WARNING in inc_nlink
2023/05/03 05:22 linux-5.15.y 8a7f2a5c5aa1 48e0a81d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 WARNING in inc_nlink
2023/05/02 23:35 linux-5.15.y 8a7f2a5c5aa1 48e0a81d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 WARNING in inc_nlink
2023/05/02 16:37 linux-5.15.y 8a7f2a5c5aa1 52d40fd2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 WARNING in inc_nlink
2023/05/02 11:29 linux-5.15.y 8a7f2a5c5aa1 52d40fd2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 WARNING in inc_nlink
2023/05/01 10:18 linux-5.15.y 8a7f2a5c5aa1 62df2017 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 WARNING in inc_nlink
2023/05/01 05:34 linux-5.15.y 8a7f2a5c5aa1 62df2017 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 WARNING in inc_nlink
2023/04/29 04:26 linux-5.15.y f48aeeaaa64c 62df2017 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 WARNING in inc_nlink
* Struck through repros no longer work on HEAD.