syzbot


KASAN: slab-use-after-free Read in jfs_syncpt

Status: upstream: reported C repro on 2025/06/21 09:40
Bug presence: origin:upstream
[Documentation on labels]
Reported-by: syzbot+1473770ca06b052afcaa@syzkaller.appspotmail.com
First crash: 123d, last: 9d13h
Bug presence (1)
Date Name Commit Repro Result
2025/06/29 upstream (ToT) dfba48a70cb6 C [report] general protection fault in lmLogSync
Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Read in jfs_syncpt jfs 19 C inconclusive 1077 4h14m 623d 0/29 upstream: reported C repro on 2024/02/07 09:29
linux-5.15 KASAN: use-after-free Read in jfs_syncpt origin:upstream 19 C 132 6h08m 617d 0/3 upstream: reported C repro on 2024/02/13 19:07
linux-6.1 KASAN: use-after-free Read in jfs_syncpt origin:upstream 19 C 158 2d19h 558d 0/3 upstream: reported C repro on 2024/04/12 18:15

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in __lock_acquire+0xff/0x7c80 kernel/locking/lockdep.c:5005
Read of size 8 at addr ffff88801db2c8d8 by task jfsCommit/111

CPU: 0 PID: 111 Comm: jfsCommit Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x16c/0x230 lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:364 [inline]
 print_report+0xac/0x220 mm/kasan/report.c:468
 kasan_report+0x117/0x150 mm/kasan/report.c:581
 __lock_acquire+0xff/0x7c80 kernel/locking/lockdep.c:5005
 lock_acquire+0x197/0x410 kernel/locking/lockdep.c:5754
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
 __mutex_lock_common kernel/locking/mutex.c:617 [inline]
 __mutex_lock+0x3b4/0xcc0 kernel/locking/mutex.c:747
 jfs_syncpt+0x25/0x90 fs/jfs/jfs_logmgr.c:1039
 txEnd+0x2e5/0x520 fs/jfs/jfs_txnmgr.c:549
 txLazyCommit fs/jfs/jfs_txnmgr.c:2684 [inline]
 jfs_lazycommit+0x5a6/0xa60 fs/jfs/jfs_txnmgr.c:2732
 kthread+0x2fa/0x390 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:152
 ret_from_fork_asm+0x11/0x20 arch/x86/entry/entry_64.S:293
 </TASK>

Allocated by task 6013:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 ____kasan_kmalloc mm/kasan/common.c:374 [inline]
 __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:383
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 open_inline_log fs/jfs/jfs_logmgr.c:1159 [inline]
 lmLogOpen+0x2df/0xfb0 fs/jfs/jfs_logmgr.c:1069
 jfs_mount_rw+0xea/0x670 fs/jfs/jfs_mount.c:257
 jfs_fill_super+0x592/0xac0 fs/jfs/super.c:565
 mount_bdev+0x22b/0x2d0 fs/super.c:1643
 legacy_get_tree+0xea/0x180 fs/fs_context.c:662
 vfs_get_tree+0x8c/0x280 fs/super.c:1764
 do_new_mount+0x24b/0xa40 fs/namespace.c:3377
 do_mount fs/namespace.c:3717 [inline]
 __do_sys_mount fs/namespace.c:3926 [inline]
 __se_sys_mount+0x2da/0x3c0 fs/namespace.c:3903
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

Freed by task 5896:
 kasan_save_stack mm/kasan/common.c:45 [inline]
 kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
 kasan_save_free_info+0x2e/0x50 mm/kasan/generic.c:522
 ____kasan_slab_free+0x126/0x1e0 mm/kasan/common.c:236
 kasan_slab_free include/linux/kasan.h:164 [inline]
 slab_free_hook mm/slub.c:1811 [inline]
 slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1837
 slab_free mm/slub.c:3830 [inline]
 __kmem_cache_free+0xba/0x1f0 mm/slub.c:3843
 lmLogClose+0x297/0x520 fs/jfs/jfs_logmgr.c:-1
 jfs_umount+0x2ef/0x3c0 fs/jfs/jfs_umount.c:114
 jfs_put_super+0x8c/0x190 fs/jfs/super.c:194
 generic_shutdown_super+0x134/0x2b0 fs/super.c:693
 kill_block_super+0x44/0x90 fs/super.c:1660
 deactivate_locked_super+0x97/0x100 fs/super.c:481
 cleanup_mnt+0x429/0x4c0 fs/namespace.c:1250
 task_work_run+0x1ce/0x250 kernel/task_work.c:239
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xe6/0x110 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xf6/0x180 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:291 [inline]
 syscall_exit_to_user_mode+0x1a/0x50 kernel/entry/common.c:302
 do_syscall_64+0x61/0xb0 arch/x86/entry/common.c:87
 entry_SYSCALL_64_after_hwframe+0x68/0xd2

The buggy address belongs to the object at ffff88801db2c800
 which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 216 bytes inside of
 freed 1024-byte region [ffff88801db2c800, ffff88801db2cc00)

The buggy address belongs to the physical page:
page:ffffea000076ca00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1db28
head:ffffea000076ca00 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
anon flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888017841dc0 0000000000000000 dead000000000001
raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 5869, tgid 5869 (syz-executor), ts 83559712291, free_ts 83548464657
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1cd/0x210 mm/page_alloc.c:1554
 prep_new_page mm/page_alloc.c:1561 [inline]
 get_page_from_freelist+0x195c/0x19f0 mm/page_alloc.c:3191
 __alloc_pages+0x1e3/0x460 mm/page_alloc.c:4457
 alloc_slab_page+0x5d/0x170 mm/slub.c:1881
 allocate_slab mm/slub.c:2028 [inline]
 new_slab+0x87/0x2e0 mm/slub.c:2081
 ___slab_alloc+0xc6d/0x1300 mm/slub.c:3253
 __slab_alloc mm/slub.c:3339 [inline]
 __slab_alloc_node mm/slub.c:3392 [inline]
 slab_alloc_node mm/slub.c:3485 [inline]
 __kmem_cache_alloc_node+0x1a2/0x260 mm/slub.c:3534
 __do_kmalloc_node mm/slab_common.c:1006 [inline]
 __kmalloc_node+0xa4/0x230 mm/slab_common.c:1014
 kmalloc_node include/linux/slab.h:620 [inline]
 kvmalloc_node+0x70/0x180 mm/util.c:617
 kvmalloc include/linux/slab.h:738 [inline]
 kvmalloc_array include/linux/slab.h:756 [inline]
 bpf_int_jit_compile+0x34d/0x1130 arch/x86/net/bpf_jit_comp.c:2864
 bpf_prog_select_runtime+0x490/0x7e0 kernel/bpf/core.c:2405
 bpf_migrate_filter net/core/filter.c:1308 [inline]
 bpf_prepare_filter+0x1148/0x12f0 net/core/filter.c:1356
 bpf_prog_create_from_user+0x2d2/0x420 net/core/filter.c:1450
 seccomp_prepare_filter kernel/seccomp.c:680 [inline]
 seccomp_prepare_user_filter kernel/seccomp.c:717 [inline]
 seccomp_set_mode_filter kernel/seccomp.c:1935 [inline]
 do_seccomp+0x7ac/0xd90 kernel/seccomp.c:2055
 __do_sys_prctl kernel/sys.c:2517 [inline]
 __se_sys_prctl+0xac4/0x1490 kernel/sys.c:2435
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x55/0xb0 arch/x86/entry/common.c:81
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1154 [inline]
 free_unref_page_prepare+0x7ce/0x8e0 mm/page_alloc.c:2336
 free_unref_page+0x32/0x2e0 mm/page_alloc.c:2429
 __slab_free+0x35e/0x410 mm/slub.c:3736
 qlink_free mm/kasan/quarantine.c:166 [inline]
 qlist_free_all+0x75/0xe0 mm/kasan/quarantine.c:185
 kasan_quarantine_reduce+0x143/0x160 mm/kasan/quarantine.c:292
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:305
 kasan_slab_alloc include/linux/kasan.h:188 [inline]
 slab_post_alloc_hook+0x6e/0x4d0 mm/slab.h:767
 slab_alloc_node mm/slub.c:3495 [inline]
 __kmem_cache_alloc_node+0x13e/0x260 mm/slub.c:3534
 __do_kmalloc_node mm/slab_common.c:1006 [inline]
 __kmalloc+0xa4/0x240 mm/slab_common.c:1020
 kmalloc include/linux/slab.h:604 [inline]
 kzalloc include/linux/slab.h:721 [inline]
 ops_init+0x8b/0x640 net/core/net_namespace.c:129
 setup_net+0x3a5/0xa00 net/core/net_namespace.c:343
 copy_net_ns+0x36d/0x5e0 net/core/net_namespace.c:520
 create_new_namespaces+0x3d3/0x6f0 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0x11a/0x160 kernel/nsproxy.c:228
 ksys_unshare+0x4c0/0x890 kernel/fork.c:3439
 __do_sys_unshare kernel/fork.c:3510 [inline]
 __se_sys_unshare kernel/fork.c:3508 [inline]
 __x64_sys_unshare+0x38/0x40 kernel/fork.c:3508

Memory state around the buggy address:
 ffff88801db2c780: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88801db2c800: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88801db2c880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                    ^
 ffff88801db2c900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801db2c980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (19):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/09/30 08:59 linux-6.6.y 147338df3487 86341da6 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
2025/08/18 03:52 linux-6.6.y bb9c90ab9c5a 1804e95e .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
2025/06/22 06:37 linux-6.6.y 6282921b6825 d6cdfb8a .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
2025/08/23 01:11 linux-6.6.y bb9c90ab9c5a bf27483f .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro (corrupt fs)] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
2025/10/13 12:26 linux-6.6.y 655054d2c3c1 b6605ba8 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
2025/10/10 01:58 linux-6.6.y e617101e5626 ff1712fe .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
2025/10/09 11:34 linux-6.6.y e617101e5626 7e2882b3 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
2025/09/24 05:30 linux-6.6.y af1544b5d072 0abd0691 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
2025/09/19 08:34 linux-6.6.y 60a9e718726f e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
2025/09/11 23:02 linux-6.6.y 60a9e718726f e2beed91 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
2025/08/28 20:09 linux-6.6.y cc1a1c5b404a d401b9d7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
2025/08/24 22:13 linux-6.6.y bb9c90ab9c5a bf27483f .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
2025/08/09 22:31 linux-6.6.y 3a8ababb8b6a 32a0e5ed .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
2025/07/18 22:19 linux-6.6.y d96eb99e2f0e 7117feec .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
2025/07/14 06:07 linux-6.6.y 59a2de10b81a 3cda49cf .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
2025/07/05 09:31 linux-6.6.y 3f5b4c104b7d 4f67c4ae .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
2025/07/03 19:02 linux-6.6.y 3f5b4c104b7d 115ceea7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
2025/06/27 12:50 linux-6.6.y 3f5b4c104b7d 803ce19b .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
2025/06/21 09:39 linux-6.6.y 6282921b6825 d6cdfb8a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-6-kasan KASAN: slab-use-after-free Read in jfs_syncpt
* Struck through repros no longer work on HEAD.