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KMSAN: uninit-value in txLock

Status: upstream: reported C repro on 2026/01/22 18:49
Subsystems: jfs
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+d3a57c32b9112d7b01ec@syzkaller.appspotmail.com
First crash: 114d, last: 30d
▶ ▼ ✨ AI Jobs (2)
ID Workflow Result Correct Bug Created Started Finished Revision Error
d1a896d3-6112-46f1-8b60-2eaf77144e41 assessment-security DenialOfService: ✅ Exploitable: ❌ FilesystemTrigger: ✅ NetworkTrigger: ❌ PeripheralTrigger: ✅ RemoteTrigger: ❌ Unprivileged: ❌ UserNamespace: ❌ VMGuestTrigger: ❌ VMHostTrigger: ❌ ❓ KMSAN: uninit-value in txLock 2026/05/12 03:28 2026/05/12 03:47 2026/05/12 04:36 d168f2605715ec7b7ab6840d636f69c758e424d9
ec2d6a19-e6e6-461c-84dd-4636862dad21 patching 💥 KMSAN: uninit-value in txLock 2026/01/23 15:02 2026/01/24 07:59 2026/01/24 08:12 40acda8acc843b8f5cc068eaad3b6b217e5a9de6 no output from test machine
▶ ▼ Discussions (3)
Title Replies (including bot) Last reply
[syzbot] [jfs?] KMSAN: uninit-value in txLock 0 (8) 2026/04/17 19:11
Subject: [PATCH RFC] jfs: fix KMSAN warning in txLock - need guidance 1 (1) 2026/01/23 09:12
[PATCH RFC] jfs: fix KMSAN warning in txLock - need guidance 1 (1) 2026/01/23 09:10
▶ ▼ Last patch testing requests (11)
Created Duration User Patch Repo Result
2026/04/17 19:11 1m tristmd@gmail.com patch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master error
2026/04/17 16:19 21m tristmd@gmail.com patch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master report log
2026/04/17 13:30 18m tristmd@gmail.com patch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master error
2026/04/17 10:11 1h01m tristmd@gmail.com patch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master report log
2026/04/13 03:17 1h05m retest repro upstream report log
2026/04/13 03:17 38m retest repro upstream report log
2026/02/02 02:30 29m retest repro upstream error
2026/02/02 02:30 21m retest repro upstream report log
2026/01/23 05:33 2h06m kartikey406@gmail.com patch upstream report log
2026/01/23 05:12 2h47m kartikey406@gmail.com patch upstream report log
2026/01/23 05:31 49m kartikey406@gmail.com patch git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git maste error

Sample crash report:
=====================================================
BUG: KMSAN: uninit-value in txLock+0x13a2/0x2900 fs/jfs/jfs_txnmgr.c:659
 txLock+0x13a2/0x2900 fs/jfs/jfs_txnmgr.c:659
 xtTruncate+0x1002/0x5050 fs/jfs/jfs_xtree.c:2337
 jfs_truncate_nolock+0x223/0x670 fs/jfs/inode.c:396
 jfs_truncate fs/jfs/inode.c:420 [inline]
 jfs_write_failed+0x207/0x3c0 fs/jfs/inode.c:295
 jfs_write_end+0xcc/0x110 fs/jfs/inode.c:322
 generic_perform_write+0x999/0x1050 mm/filemap.c:4335
 __generic_file_write_iter+0x213/0x460 mm/filemap.c:4431
 generic_file_write_iter+0x131/0x980 mm/filemap.c:4457
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0xbe2/0x15d0 fs/read_write.c:686
 ksys_pwrite64 fs/read_write.c:793 [inline]
 __do_sys_pwrite64 fs/read_write.c:801 [inline]
 __se_sys_pwrite64 fs/read_write.c:798 [inline]
 __x64_sys_pwrite64+0x2ab/0x3b0 fs/read_write.c:798
 x64_sys_call+0xbaf/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:19
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd3/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 __alloc_frozen_pages_noprof+0x421/0xab0 mm/page_alloc.c:5263
 alloc_pages_mpol+0x328/0x860 mm/mempolicy.c:2486
 alloc_frozen_pages_noprof mm/mempolicy.c:2557 [inline]
 alloc_pages_noprof+0x102/0x280 mm/mempolicy.c:2577
 vm_area_alloc_pages mm/vmalloc.c:3649 [inline]
 __vmalloc_area_node mm/vmalloc.c:3863 [inline]
 __vmalloc_node_range_noprof+0xa94/0x2d90 mm/vmalloc.c:4051
 __vmalloc_node_noprof mm/vmalloc.c:4111 [inline]
 vmalloc_noprof+0xce/0x140 mm/vmalloc.c:4146
 txInit+0xb5c/0xfa0 fs/jfs/jfs_txnmgr.c:297
 init_jfs_fs+0x1b2/0xcb0 fs/jfs/super.c:977
 do_one_initcall+0x22b/0xad0 init/main.c:1378
 do_initcall_level+0x157/0x2e0 init/main.c:1440
 do_initcalls+0x176/0x310 init/main.c:1456
 do_basic_setup+0x1d/0x30 init/main.c:1475
 kernel_init_freeable+0x214/0x430 init/main.c:1688
 kernel_init+0x2f/0x5e0 init/main.c:1578
 ret_from_fork+0x208/0x710 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246

CPU: 1 UID: 0 PID: 6025 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT(none) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
=====================================================

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/01/18 23:15 upstream e84d960149e7 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci-upstream-kmsan-gce-root KMSAN: uninit-value in txLock
2026/01/18 20:56 upstream e84d960149e7 d6526ea3 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci-upstream-kmsan-gce-root KMSAN: uninit-value in txLock
2026/01/18 18:45 upstream e84d960149e7 d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kmsan-gce-root KMSAN: uninit-value in txLock
* Struck through repros no longer work on HEAD.