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kernel BUG in jfs_unlink

Status: upstream: reported C repro on 2024/07/24 18:05
Subsystems: jfs
[Documentation on labels]
Reported-by: syzbot+41b43444de86db4c5ed1@syzkaller.appspotmail.com
First crash: 718d, last: 69d
Cause bisection: the issue happens on the oldest tested release (bisect log)
Crash: kernel BUG in jfs_unlink (log)
Repro: C syz .config
  
Fix bisection: failed (error log, bisect log)
  
▶ ▼ ✨ AI Jobs (6)
ID Workflow Result Correct Bug Created Started Finished Revision Error
04f1e450-98a4-49cc-b4c1-b10fc019ebbc assessment-security 💥 kernel BUG in jfs_unlink 2026/07/05 04:04 2026/07/05 04:04 2026/07/05 04:22 93f579545ae410f5bccfa141d2e7bf03178f036c 
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/441ccb086b3e7b3a24...
truncated to first 200 bytes; open job for full error
b4a7ef3d-789c-4c46-b769-7fefecf6ed36 assessment-security 💥 kernel BUG in jfs_unlink 2026/06/18 03:31 2026/06/18 03:31 2026/06/18 03:51 b62b3ded1759f79b37600c5ffe2b0a81b919b0b0 
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/441ccb086b3e7b3a24...
truncated to first 200 bytes; open job for full error
eae5dd4e-ca1f-4dd6-90d9-f38c48145700 assessment-security 💥 kernel BUG in jfs_unlink 2026/06/09 23:33 2026/06/09 23:33 2026/06/10 00:01 c36c07f6c1f2230a36374cbd22235f635e8f9284 
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/441ccb086b3e7b3a24...
truncated to first 200 bytes; open job for full error
2857ef02-1197-4f3b-a965-2e9751e7e4e2 assessment-security 💥 kernel BUG in jfs_unlink 2026/06/04 01:19 2026/06/04 01:19 2026/06/04 01:36 62fe15281f5011cd203d8845b8767b10e7443aa5 
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/441ccb086b3e7b3a24...
truncated to first 200 bytes; open job for full error
8a411e10-12cc-4798-a10e-7603ba9e1736 assessment-security 💥 kernel BUG in jfs_unlink 2026/06/01 12:52 2026/06/01 12:52 2026/06/01 13:09 6b4a844333e83556da95d61d7f207e7ef5cd4bc6 
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/441ccb086b3e7b3a24...
truncated to first 200 bytes; open job for full error
ff2d10d9-d197-4aed-8159-12d74686f6a5 assessment-security 💥 kernel BUG in jfs_unlink 2026/05/15 17:22 2026/05/15 17:22 2026/05/15 17:50 efdaf0f9b8bfc56ea6d17bea15a64f4591cc712d 
failed to run ["make" "KERNELVERSION=syzkaller" "KERNELRELEASE=syzkaller" "LOCALVERSION=-syzkaller" "-j" "32" "ARCH=x86_64" "CC=ccache clang" "LD=ld.lld" "O=/app/workdir/cache/build/441ccb086b3e7b3a24...
truncated to first 200 bytes; open job for full error
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[PATCH] VFS: check i_nlink count before trying to unlink 2 (2) 2024/09/07 19:02
[syzbot] [jfs?] kernel BUG in jfs_unlink 0 (3) 2024/09/07 16:48
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.6 kernel BUG in jfs_unlink origin:upstream -1 C error 1 138d 138d 0/2 upstream: reported C repro on 2026/02/22 02:11
linux-5.15 kernel BUG in jfs_unlink -1 1 375d 375d 0/3 auto-obsoleted due to no activity on 2025/10/07 19:02
linux-6.1 kernel BUG in jfs_unlink -1 C error 1 75d 75d 0/3 upstream: reported C repro on 2026/04/26 03:49
▶ ▼ Last patch testing requests (11)
Created Duration User Patch Repo Result
2026/06/27 03:47 18m retest repro upstream log
2026/05/19 02:03 40m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci OK log
2026/05/18 21:22 3h16m retest repro linux-next log
2026/05/18 21:20 3h06m retest repro linux-next log
2026/04/02 01:49 13m retest repro upstream report log
2026/03/09 20:46 17m retest repro linux-next report log
2026/03/09 19:09 1h22m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci error
2025/12/23 00:06 21m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci report log
2025/11/07 06:22 13m retest repro upstream report log
2025/10/03 01:02 40m retest repro git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci report log
2024/09/07 16:48 20m ghanshyam1898@gmail.com patch upstream OK log
▶ ▼ Fix bisection attempts (11)
Created Duration User Patch Repo Result
2026/01/22 01:34 2m bisect fix upstream error job log
2025/12/08 21:55 1h50m bisect fix upstream OK (0) job log log
2025/08/28 04:12 2h18m bisect fix upstream OK (0) job log log
2025/06/25 01:34 1h57m bisect fix upstream OK (0) job log log
2025/05/25 10:14 2h46m bisect fix upstream OK (0) job log log
2025/04/22 05:17 3h42m bisect fix upstream OK (0) job log log
2025/03/19 15:28 3h31m bisect fix upstream OK (0) job log log
2025/02/16 12:34 1h30m bisect fix upstream OK (0) job log log
2025/01/16 20:33 1h56m bisect fix upstream OK (0) job log log
2024/11/30 12:57 2h16m bisect fix upstream OK (0) job log log
2024/10/16 22:37 2h20m bisect fix upstream OK (0) job log log

Sample crash report:
BUG at fs/jfs/namei.c:513 assert(ip->i_nlink)
------------[ cut here ]------------
kernel BUG at fs/jfs/namei.c:513!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN PTI
CPU: 1 UID: 0 PID: 5224 Comm: syz-executor204 Not tainted 6.11.0-rc6-syzkaller-00017-gc9f016e72b5c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
RIP: 0010:jfs_unlink+0xafd/0xb30 fs/jfs/namei.c:513
Code: e8 c8 5d 91 08 e8 83 f0 73 fe 48 c7 c7 20 9c 22 8c 48 c7 c6 e0 99 22 8c ba 01 02 00 00 48 c7 c1 60 9c 22 8c e8 64 5e 8e 08 90 <0f> 0b e8 5c f0 73 fe 48 c7 c7 20 9c 22 8c 48 c7 c6 e0 99 22 8c ba
RSP: 0018:ffffc9000344fbe0 EFLAGS: 00010246
RAX: 000000000000002d RBX: 0000000000000000 RCX: 44cfc770ad800100
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffc9000344fd10 R08: ffffffff8174016c R09: 1ffff92000689f1c
R10: dffffc0000000000 R11: fffff52000689f1d R12: 0000000000000000
R13: ffffc9000344fc60 R14: 1ffff92000689f8c R15: ffff888072c33248
FS:  0000555577bcd380(0000) GS:ffff8880b8900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000045bdd0 CR3: 000000007ab8a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 vfs_unlink+0x365/0x650 fs/namei.c:4422
 do_unlinkat+0x4ae/0x830 fs/namei.c:4486
 __do_sys_unlink fs/namei.c:4534 [inline]
 __se_sys_unlink fs/namei.c:4532 [inline]
 __x64_sys_unlink+0x47/0x50 fs/namei.c:4532
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f69ef25fad7
Code: 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 b8 57 00 00 00 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:00007fff4544dac8 EFLAGS: 00000206 ORIG_RAX: 0000000000000057
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f69ef25fad7
RDX: 00007fff4544daf0 RSI: 00007fff4544db80 RDI: 00007fff4544db80
RBP: 00007fff4544db80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000100 R11: 0000000000000206 R12: 00007fff4544ec70
R13: 0000555577bd6700 R14: 0000000000000001 R15: 431bde82d7b634db
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:jfs_unlink+0xafd/0xb30 fs/jfs/namei.c:513
Code: e8 c8 5d 91 08 e8 83 f0 73 fe 48 c7 c7 20 9c 22 8c 48 c7 c6 e0 99 22 8c ba 01 02 00 00 48 c7 c1 60 9c 22 8c e8 64 5e 8e 08 90 <0f> 0b e8 5c f0 73 fe 48 c7 c7 20 9c 22 8c 48 c7 c6 e0 99 22 8c ba
RSP: 0018:ffffc9000344fbe0 EFLAGS: 00010246
RAX: 000000000000002d RBX: 0000000000000000 RCX: 44cfc770ad800100
RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000000
RBP: ffffc9000344fd10 R08: ffffffff8174016c R09: 1ffff92000689f1c
R10: dffffc0000000000 R11: fffff52000689f1d R12: 0000000000000000
R13: ffffc9000344fc60 R14: 1ffff92000689f8c R15: ffff888072c33248
FS:  0000555577bcd380(0000) GS:ffff8880b8900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000045bdd0 CR3: 000000007ab8a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

Crashes (23):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/09/02 11:32 upstream c9f016e72b5c 1eda0d14 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs kernel BUG in jfs_unlink
2026/02/23 17:49 linux-next d4906ae14a5f 305c0ec5 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci-upstream-linux-next-kasan-gce-root kernel BUG in jfs_unlink
2026/05/02 16:02 upstream f1a5e78a55eb a0d91488 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in jfs_unlink
2026/05/01 14:34 upstream 26fd6bff2c05 753c55b9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in jfs_unlink
2025/08/30 20:49 upstream 11e7861d680c 807a3b61 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in jfs_unlink
2024/09/02 10:40 upstream c9f016e72b5c 1eda0d14 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in jfs_unlink
2024/07/21 22:43 upstream 2c9b3512402e b88348e9 .config console log report info [disk image] [vmlinux] [kernel image] ci2-upstream-fs kernel BUG in jfs_unlink
2025/07/10 15:45 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci ec4801305969 19d4829f .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci-upstream-gce-arm64 kernel BUG in jfs_unlink
2024/08/15 23:56 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7c626ce4bae1 e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 kernel BUG in jfs_unlink
2024/08/15 23:55 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7c626ce4bae1 e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 kernel BUG in jfs_unlink
2024/08/15 23:54 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7c626ce4bae1 e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 kernel BUG in jfs_unlink
2024/08/15 23:54 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7c626ce4bae1 e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 kernel BUG in jfs_unlink
2024/08/15 23:54 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7c626ce4bae1 e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 kernel BUG in jfs_unlink
2024/08/15 23:54 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7c626ce4bae1 e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 kernel BUG in jfs_unlink
2024/08/15 23:53 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7c626ce4bae1 e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 kernel BUG in jfs_unlink
2024/08/15 23:52 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7c626ce4bae1 e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 kernel BUG in jfs_unlink
2024/08/15 23:52 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7c626ce4bae1 e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 kernel BUG in jfs_unlink
2024/08/15 23:52 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7c626ce4bae1 e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 kernel BUG in jfs_unlink
2024/08/15 23:50 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7c626ce4bae1 e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 kernel BUG in jfs_unlink
2024/08/15 23:50 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7c626ce4bae1 e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 kernel BUG in jfs_unlink
2024/08/15 23:50 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7c626ce4bae1 e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 kernel BUG in jfs_unlink
2024/08/15 23:50 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7c626ce4bae1 e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 kernel BUG in jfs_unlink
2024/08/15 23:50 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7c626ce4bae1 e4bacdaf .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 kernel BUG in jfs_unlink
* Struck through repros no longer work on HEAD.