[syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    0f3be52b8e37 Merge branch 'for-next/core' into for-kernelci
git tree:       git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=17509ce2580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=714d45b6135c308e
dashboard link: https://syzkaller.appspot.com/bug?extid=ecf51a7ccb6b1394e90c
compiler:       Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/a2c3b345c3da/disk-0f3be52b.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/54368457365a/vmlinux-0f3be52b.xz
kernel image: https://storage.googleapis.com/syzbot-assets/3544cf9b3f24/Image-0f3be52b.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ecf51a7ccb6b1394e90c@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in lbmIODone+0xf68/0x12e8 fs/jfs/jfs_logmgr.c:2184
Read of size 4 at addr ffff0000fa465408 by task ksoftirqd/1/23

CPU: 1 UID: 0 PID: 23 Comm: ksoftirqd/1 Not tainted syzkaller #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/30/2025
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 print_address_description+0xa8/0x238 mm/kasan/report.c:378
 print_report+0x68/0x84 mm/kasan/report.c:482
 kasan_report+0xb0/0x110 mm/kasan/report.c:595
 __asan_report_load4_noabort+0x20/0x2c mm/kasan/report_generic.c:380
 lbmIODone+0xf68/0x12e8 fs/jfs/jfs_logmgr.c:2184
 bio_endio+0x858/0x894 block/bio.c:1651
 blk_update_request+0x474/0xba8 block/blk-mq.c:989
 blk_mq_end_request+0x54/0x88 block/blk-mq.c:1151
 lo_complete_rq+0x124/0x274 drivers/block/loop.c:314
 blk_complete_reqs block/blk-mq.c:1226 [inline]
 blk_done_softirq+0x11c/0x168 block/blk-mq.c:1231
 handle_softirqs+0x328/0xc88 kernel/softirq.c:579
 run_ksoftirqd+0x70/0xc0 kernel/softirq.c:968
 smpboot_thread_fn+0x4d8/0x9cc kernel/smpboot.c:160
 kthread+0x5fc/0x75c kernel/kthread.c:463
 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:844

Allocated by task 6893:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:68
 kasan_save_alloc_info+0x44/0x54 mm/kasan/generic.c:562
 poison_kmalloc_redzone mm/kasan/common.c:388 [inline]
 __kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:405
 kasan_kmalloc include/linux/kasan.h:260 [inline]
 __kmalloc_cache_noprof+0x2a4/0x3fc mm/slub.c:4407
 kmalloc_noprof include/linux/slab.h:905 [inline]
 lbmLogInit fs/jfs/jfs_logmgr.c:1822 [inline]
 lmLogInit+0x690/0x1a9c fs/jfs/jfs_logmgr.c:1270
 open_inline_log fs/jfs/jfs_logmgr.c:1175 [inline]
 lmLogOpen+0x41c/0xd5c fs/jfs/jfs_logmgr.c:1069
 jfs_mount_rw+0xe4/0x548 fs/jfs/jfs_mount.c:257
 jfs_fill_super+0x5d4/0xb6c fs/jfs/super.c:532
 get_tree_bdev_flags+0x360/0x414 fs/super.c:1692
 get_tree_bdev+0x2c/0x3c fs/super.c:1715
 jfs_get_tree+0x28/0x38 fs/jfs/super.c:635
 vfs_get_tree+0x90/0x28c fs/super.c:1815
 do_new_mount+0x278/0x7f4 fs/namespace.c:3808
 path_mount+0x5b4/0xde0 fs/namespace.c:4123
 do_mount fs/namespace.c:4136 [inline]
 __do_sys_mount fs/namespace.c:4347 [inline]
 __se_sys_mount fs/namespace.c:4324 [inline]
 __arm64_sys_mount+0x3e8/0x468 fs/namespace.c:4324
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

Freed by task 6536:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:68
 kasan_save_free_info+0x58/0x70 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:243 [inline]
 __kasan_slab_free+0x74/0x98 mm/kasan/common.c:275
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2422 [inline]
 slab_free mm/slub.c:4695 [inline]
 kfree+0x17c/0x474 mm/slub.c:4894
 lbmLogShutdown fs/jfs/jfs_logmgr.c:1865 [inline]
 lmLogShutdown+0x36c/0x700 fs/jfs/jfs_logmgr.c:1684
 lmLogClose+0x244/0x4c4 fs/jfs/jfs_logmgr.c:1460
 jfs_umount+0x26c/0x350 fs/jfs/jfs_umount.c:114
 jfs_put_super+0x90/0x188 fs/jfs/super.c:194
 generic_shutdown_super+0x12c/0x2b8 fs/super.c:643
 kill_block_super+0x44/0x90 fs/super.c:1766
 deactivate_locked_super+0xc4/0x12c fs/super.c:474
 deactivate_super+0xe0/0x100 fs/super.c:507
 cleanup_mnt+0x31c/0x3ac fs/namespace.c:1375
 __cleanup_mnt+0x20/0x30 fs/namespace.c:1382
 task_work_run+0x1dc/0x260 kernel/task_work.c:227
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 exit_to_user_mode_loop+0xfc/0x168 kernel/entry/common.c:43
 exit_to_user_mode_prepare include/linux/irq-entry-common.h:225 [inline]
 arm64_exit_to_user_mode arch/arm64/kernel/entry-common.c:103 [inline]
 el0_svc+0x170/0x254 arch/arm64/kernel/entry-common.c:745
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:763
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

The buggy address belongs to the object at ffff0000fa465400
 which belongs to the cache kmalloc-192 of size 192
The buggy address is located 8 bytes inside of
 freed 192-byte region [ffff0000fa465400, ffff0000fa4654c0)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x13a465
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 05ffc00000000000 ffff0000c00013c0 fffffdffc3070180 0000000000000004
raw: 0000000000000000 0000000000100010 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000fa465300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff0000fa465380: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
>ffff0000fa465400: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff0000fa465480: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff0000fa465500: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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#syz undup

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    e6efabc0afca Add linux-next specific files for 20260414
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=161a18ce580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=56c2b36de3316f1b
dashboard link: https://syzkaller.appspot.com/bug?extid=ecf51a7ccb6b1394e90c
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=107784ce580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e7099cbf73e4/disk-e6efabc0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/439c402df1b9/vmlinux-e6efabc0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fc0c0175fc76/bzImage-e6efabc0.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/01761e564f3f/mount_0.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=168401ba580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ecf51a7ccb6b1394e90c@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in lbmIODone+0x1312/0x16c0 fs/jfs/jfs_logmgr.c:2192
Read of size 4 at addr ffff888032de1208 by task ksoftirqd/1/31

CPU: 1 UID: 0 PID: 31 Comm: ksoftirqd/1 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 lbmIODone+0x1312/0x16c0 fs/jfs/jfs_logmgr.c:2192
 blk_update_request+0x57e/0xe60 block/blk-mq.c:1016
 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1178
 blk_complete_reqs block/blk-mq.c:1253 [inline]
 blk_done_softirq+0x10a/0x160 block/blk-mq.c:1258
 handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622
 run_ksoftirqd+0x52/0x180 kernel/softirq.c:1076
 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 6248:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x3a6/0x690 mm/slub.c:5415
 kmalloc_noprof include/linux/slab.h:950 [inline]
 lbmLogInit fs/jfs/jfs_logmgr.c:1819 [inline]
 lmLogInit+0x3e5/0x1a00 fs/jfs/jfs_logmgr.c:1267
 open_inline_log fs/jfs/jfs_logmgr.c:1173 [inline]
 lmLogOpen+0x4e1/0xfa0 fs/jfs/jfs_logmgr.c:1067
 jfs_mount_rw+0xee/0x670 fs/jfs/jfs_mount.c:257
 jfs_fill_super+0x754/0xd80 fs/jfs/super.c:532
 get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694
 vfs_get_tree+0x92/0x2a0 fs/super.c:1754
 fc_mount fs/namespace.c:1193 [inline]
 do_new_mount_fc fs/namespace.c:3758 [inline]
 do_new_mount+0x341/0xd30 fs/namespace.c:3834
 do_mount fs/namespace.c:4167 [inline]
 __do_sys_mount fs/namespace.c:4399 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4376
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5959:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2689 [inline]
 slab_free mm/slub.c:6246 [inline]
 kfree+0x1c5/0x6c0 mm/slub.c:6561
 lbmLogShutdown fs/jfs/jfs_logmgr.c:1862 [inline]
 lmLogShutdown+0x456/0x850 fs/jfs/jfs_logmgr.c:1681
 lmLogClose+0x28a/0x520 fs/jfs/jfs_logmgr.c:1457
 jfs_umount+0x2fb/0x3d0 fs/jfs/jfs_umount.c:124
 jfs_put_super+0x8c/0x190 fs/jfs/super.c:194
 generic_shutdown_super+0x13d/0x2d0 fs/super.c:646
 kill_block_super+0x44/0x90 fs/super.c:1725
 deactivate_locked_super+0xbc/0x130 fs/super.c:476
 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline]
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888032de1200
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 8 bytes inside of
 freed 256-byte region [ffff888032de1200, ffff888032de1300)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x32de0
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88801a02cb40 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88801a02cb40 dead000000000100 dead000000000122
head: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 0080000000000001 ffffffffffffff81 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5948, tgid 5948 (syz-executor), ts 136932809553, free_ts 131716582127
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1858
 prep_new_page mm/page_alloc.c:1866 [inline]
 get_page_from_freelist+0x27d6/0x2850 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5226
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x33c/0x3d0 mm/slub.c:7251
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x373/0x720 mm/slub.c:4651
 alloc_from_pcs mm/slub.c:4749 [inline]
 slab_alloc_node mm/slub.c:4883 [inline]
 __do_kmalloc_node mm/slub.c:5294 [inline]
 __kmalloc_noprof+0x530/0x7b0 mm/slub.c:5307
 kmalloc_noprof include/linux/slab.h:954 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 fib_create_info+0x1723/0x31f0 net/ipv4/fib_semantics.c:1400
 fib_table_insert+0xc8/0x1b50 net/ipv4/fib_trie.c:1212
 fib_magic+0x434/0x510 net/ipv4/fib_frontend.c:1134
 fib_add_ifaddr+0x38d/0x5f0 net/ipv4/fib_frontend.c:1171
 fib_netdev_event+0x382/0x490 net/ipv4/fib_frontend.c:1516
 notifier_call_chain+0x1ad/0x3d0 kernel/notifier.c:85
 call_netdevice_notifiers_extack net/core/dev.c:2287 [inline]
 call_netdevice_notifiers net/core/dev.c:2301 [inline]
 __dev_notify_flags+0x1a9/0x310 net/core/dev.c:9849
 netif_change_flags+0xe8/0x1a0 net/core/dev.c:9878
 do_setlink+0xf82/0x4590 net/core/rtnetlink.c:3180
page last free pid 5958 tgid 5958 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1402 [inline]
 __free_frozen_pages+0xf9b/0x10f0 mm/page_alloc.c:2943
 __slab_free+0x252/0x2a0 mm/slub.c:5608
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4569 [inline]
 slab_alloc_node mm/slub.c:4898 [inline]
 kmem_cache_alloc_node_noprof+0x22a/0x6e0 mm/slub.c:4950
 __alloc_skb+0x1d0/0x7d0 net/core/skbuff.c:702
 alloc_skb include/linux/skbuff.h:1383 [inline]
 nlmsg_new include/net/netlink.h:1055 [inline]
 netlink_ack+0x146/0xa50 net/netlink/af_netlink.c:2487
 netlink_rcv_skb+0x2b6/0x4b0 net/netlink/af_netlink.c:2556
 netlink_unicast_kernel net/netlink/af_netlink.c:1318 [inline]
 netlink_unicast+0x780/0x920 net/netlink/af_netlink.c:1344
 netlink_sendmsg+0x813/0xb40 net/netlink/af_netlink.c:1894
 sock_sendmsg_nosec net/socket.c:787 [inline]
 __sock_sendmsg net/socket.c:802 [inline]
 __sys_sendto+0x67f/0x710 net/socket.c:2265
 __do_sys_sendto net/socket.c:2272 [inline]
 __se_sys_sendto net/socket.c:2268 [inline]
 __x64_sys_sendto+0xde/0x100 net/socket.c:2268
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888032de1100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888032de1180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888032de1200: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff888032de1280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888032de1300: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit:    e6efabc0afca Add linux-next specific files for 20260414
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17ee18ce580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=56c2b36de3316f1b
dashboard link: https://syzkaller.appspot.com/bug?extid=ecf51a7ccb6b1394e90c
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11dc01ba580000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=173bfb02580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/e7099cbf73e4/disk-e6efabc0.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/439c402df1b9/vmlinux-e6efabc0.xz
kernel image: https://storage.googleapis.com/syzbot-assets/fc0c0175fc76/bzImage-e6efabc0.xz
mounted in repro: https://storage.googleapis.com/syzbot-assets/81df22d6836d/mount_0.gz
  fsck result: failed (log: https://syzkaller.appspot.com/x/fsck.log?x=107dfcd2580000)

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+ecf51a7ccb6b1394e90c@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in lbmIODone+0x1312/0x16c0 fs/jfs/jfs_logmgr.c:2192
Read of size 4 at addr ffff88802a45a608 by task ksoftirqd/1/31

CPU: 1 UID: 0 PID: 31 Comm: ksoftirqd/1 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 lbmIODone+0x1312/0x16c0 fs/jfs/jfs_logmgr.c:2192
 blk_update_request+0x57e/0xe60 block/blk-mq.c:1016
 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1178
 blk_complete_reqs block/blk-mq.c:1253 [inline]
 blk_done_softirq+0x10a/0x160 block/blk-mq.c:1258
 handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622
 run_ksoftirqd+0x52/0x180 kernel/softirq.c:1076
 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 6106:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x3a6/0x690 mm/slub.c:5415
 kmalloc_noprof include/linux/slab.h:950 [inline]
 lbmLogInit fs/jfs/jfs_logmgr.c:1819 [inline]
 lmLogInit+0x3e5/0x1a00 fs/jfs/jfs_logmgr.c:1267
 open_inline_log fs/jfs/jfs_logmgr.c:1173 [inline]
 lmLogOpen+0x4e1/0xfa0 fs/jfs/jfs_logmgr.c:1067
 jfs_mount_rw+0xee/0x670 fs/jfs/jfs_mount.c:257
 jfs_fill_super+0x754/0xd80 fs/jfs/super.c:532
 get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694
 vfs_get_tree+0x92/0x2a0 fs/super.c:1754
 fc_mount fs/namespace.c:1193 [inline]
 do_new_mount_fc fs/namespace.c:3758 [inline]
 do_new_mount+0x341/0xd30 fs/namespace.c:3834
 do_mount fs/namespace.c:4167 [inline]
 __do_sys_mount fs/namespace.c:4399 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4376
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5969:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2689 [inline]
 slab_free mm/slub.c:6246 [inline]
 kfree+0x1c5/0x6c0 mm/slub.c:6561
 lbmLogShutdown fs/jfs/jfs_logmgr.c:1862 [inline]
 lmLogShutdown+0x456/0x850 fs/jfs/jfs_logmgr.c:1681
 lmLogClose+0x28a/0x520 fs/jfs/jfs_logmgr.c:1457
 jfs_umount+0x2fb/0x3d0 fs/jfs/jfs_umount.c:124
 jfs_put_super+0x8c/0x190 fs/jfs/super.c:194
 generic_shutdown_super+0x13d/0x2d0 fs/super.c:646
 kill_block_super+0x44/0x90 fs/super.c:1725
 deactivate_locked_super+0xbc/0x130 fs/super.c:476
 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline]
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88802a45a600
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 8 bytes inside of
 freed 256-byte region [ffff88802a45a600, ffff88802a45a700)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2a45a
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000040(head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000040 ffff88801a02cb40 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 0080000000000040 ffff88801a02cb40 dead000000000100 dead000000000122
head: 0000000000000000 0000000800100010 00000000f5000000 0000000000000000
head: 0080000000000001 ffffffffffffff81 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000002
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 155, tgid 155 (kworker/u8:6), ts 12504727555, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1858
 prep_new_page mm/page_alloc.c:1866 [inline]
 get_page_from_freelist+0x27d6/0x2850 mm/page_alloc.c:3946
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5226
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x33c/0x3d0 mm/slub.c:7251
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x373/0x720 mm/slub.c:4651
 alloc_from_pcs mm/slub.c:4749 [inline]
 slab_alloc_node mm/slub.c:4883 [inline]
 __kmalloc_cache_noprof+0x44e/0x690 mm/slub.c:5410
 kmalloc_noprof include/linux/slab.h:950 [inline]
 scsi_probe_and_add_lun+0x2f8/0x48e0 drivers/scsi/scsi_scan.c:1225
 __scsi_scan_target+0x1f0/0xe10 drivers/scsi/scsi_scan.c:1786
 scsi_scan_channel drivers/scsi/scsi_scan.c:1874 [inline]
 scsi_scan_host_selected+0x3d3/0x780 drivers/scsi/scsi_scan.c:1903
 do_scsi_scan_host drivers/scsi/scsi_scan.c:2036 [inline]
 do_scan_async+0x124/0x6f0 drivers/scsi/scsi_scan.c:2046
 async_run_entry_fn+0xa8/0x440 kernel/async.c:129
 process_one_work kernel/workqueue.c:3308 [inline]
 process_scheduled_works+0xb68/0x1910 kernel/workqueue.c:3399
 worker_thread+0xa90/0x1040 kernel/workqueue.c:3485
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
page_owner free stack trace missing

Memory state around the buggy address:
 ffff88802a45a500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88802a45a580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88802a45a600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                      ^
 ffff88802a45a680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88802a45a700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================


---
If you want syzbot to run the reproducer, reply with:
#syz test: git://repo/address.git branch-or-commit-hash
If you attach or paste a git patch, syzbot will apply it before testing.

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[Edward Adam Davis]

#syz test: upstream master

diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index 306165e61438..054cc01e4579 100644
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -1984,7 +1984,7 @@ static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp)
 		submit_bio(bio);
 	}
 
-	wait_event(bp->l_ioevent, (bp->l_flag != lbmREAD));
+	wait_event(bp->l_ioevent, (bp->l_flag == lbmDONE));
 
 	return 0;
 }

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
INFO: task hung in lbmRead

INFO: task syz.0.17:6554 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.17        state:D stack:24224 pid:6554  tgid:6552  ppid:6447   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5387 [inline]
 __schedule+0x1681/0x54c0 kernel/sched/core.c:7188
 __schedule_loop kernel/sched/core.c:7267 [inline]
 schedule+0x164/0x360 kernel/sched/core.c:7282
 lbmRead+0x41d/0x620 fs/jfs/jfs_logmgr.c:1987
 lmLogInit+0xc31/0x1a00 fs/jfs/jfs_logmgr.c:1332
 open_inline_log fs/jfs/jfs_logmgr.c:1173 [inline]
 lmLogOpen+0x4e1/0xfa0 fs/jfs/jfs_logmgr.c:1067
 jfs_mount_rw+0xee/0x670 fs/jfs/jfs_mount.c:257
 jfs_fill_super+0x754/0xd80 fs/jfs/super.c:532
 get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694
 vfs_get_tree+0x92/0x2a0 fs/super.c:1754
 fc_mount fs/namespace.c:1193 [inline]
 do_new_mount_fc fs/namespace.c:3758 [inline]
 do_new_mount+0x341/0xd30 fs/namespace.c:3834
 do_mount fs/namespace.c:4167 [inline]
 __do_sys_mount fs/namespace.c:4383 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4360
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa8f8bfda8a
RSP: 002b:00007fa8f8255e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fa8f8255ee0 RCX: 00007fa8f8bfda8a
RDX: 0000200000000400 RSI: 00002000000000c0 RDI: 00007fa8f8255ea0
RBP: 0000200000000400 R08: 00007fa8f8255ee0 R09: 000000000001c802
R10: 000000000001c802 R11: 0000000000000246 R12: 00002000000000c0
R13: 00007fa8f8255ea0 R14: 0000000000005f9a R15: 0000200000002740
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/38:
 #0: ffffffff8dfc7f00 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #0: ffffffff8dfc7f00 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 #0: ffffffff8dfc7f00 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
3 locks held by kworker/u9:0/59:
 #0: ffff88802a705138 ((wq_completion)hci2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3277 [inline]
 #0: ffff88802a705138 ((wq_completion)hci2){+.+.}-{0:0}, at: process_scheduled_works+0xa35/0x1860 kernel/workqueue.c:3385
 #1: ffffc9000125fc40 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3278 [inline]
 #1: ffffc9000125fc40 ((work_completion)(&hdev->cmd_sync_work)){+.+.}-{0:0}, at: process_scheduled_works+0xa70/0x1860 kernel/workqueue.c:3385
 #2: ffff888038d10f80 (&hdev->req_lock){+.+.}-{4:4}, at: hci_cmd_sync_work+0x1d3/0x400 net/bluetooth/hci_sync.c:331
9 locks held by kworker/u8:11/2867:
2 locks held by getty/5561:
 #0: ffff8880389230a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003cbe2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13a0 drivers/tty/n_tty.c:2211
1 lock held by syz.0.17/6554:
 #0: ffff8880395e20d0 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xac0 fs/super.c:345
1 lock held by syz.1.19/6613:
 #0: ffff88804e5d00d0 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xac0 fs/super.c:345
1 lock held by syz.2.28/6658:
 #0: ffff88805bffc0d0 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xac0 fs/super.c:345
2 locks held by syz-executor/6660:
 #0: ffff8880587a60d0 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff8880587a60d0 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff8880587a60d0 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508
 #1: ffffffff8e4545d8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1441
2 locks held by syz-executor/6692:
 #0: ffff888035d4e0d0 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff888035d4e0d0 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff888035d4e0d0 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508
 #1: ffffffff8e4545d8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1441
2 locks held by syz-executor/6720:
 #0: ffff88805a2500d0 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff88805a2500d0 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff88805a2500d0 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508
 #1: ffffffff8e4545d8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1441
2 locks held by syz-executor/6754:
 #0: ffff88803f6220d0 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock fs/super.c:58 [inline]
 #0: ffff88803f6220d0 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
 #0: ffff88803f6220d0 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508
 #1: ffffffff8e4545d8 (jfs_log_mutex){+.+.}-{4:4}, at: lmLogClose+0xb4/0x520 fs/jfs/jfs_logmgr.c:1441
1 lock held by syz.7.41/6809:
 #0: ffff8880365f80d0 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xac0 fs/super.c:345
1 lock held by syz.8.42/6838:
 #0: ffff8880399d60d0 (&type->s_umount_key#55/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xac0 fs/super.c:345

=============================================

NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x135/0x170 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline]
 watchdog+0xfd3/0x1030 kernel/hung_task.c:561
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 2867 Comm: kworker/u8:11 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Workqueue: events_unbound cfg80211_wiphy_work
RIP: 0010:reacquire_held_locks+0xf6/0x190 kernel/locking/lockdep.c:5385
Code: e2 01 89 c1 c1 e9 10 83 e1 03 41 89 c0 41 c1 e8 12 41 83 e0 01 41 89 c1 41 c1 e9 13 41 83 e1 01 c1 e8 15 45 8b 16 6a 00 41 52 <50> 41 ff 76 e4 41 ff 76 f4 e8 8c 9f ff ff 48 83 c4 28 83 f8 01 0f
RSP: 0018:ffffc9000e707820 EFLAGS: 00000046
RAX: 0000000000000000 RBX: ffffc9000e707884 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff8dfc7f00
RBP: 00000000ffffffff R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: fffffbfff1f16d97 R12: 0000000000000004
R13: 0000000000000004 R14: ffff8880324968fc R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff88812610f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055555dbfc4e8 CR3: 000000000ddb6000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 __lock_release kernel/locking/lockdep.c:5574 [inline]
 lock_release+0x199/0x3c0 kernel/locking/lockdep.c:5889
 __local_bh_enable_ip+0x98/0x2b0 kernel/softirq.c:268
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 spin_unlock_bh include/linux/spinlock_rt.h:116 [inline]
 ieee80211_ibss_work+0x344/0x10d0 net/mac80211/ibss.c:1656
 cfg80211_wiphy_work+0x2cf/0x460 net/wireless/core.c:513
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>


Tested on:

commit:         43cfbdda Merge tag 'for-linus-iommufd' of git://git.ke..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11621906580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4660d1ff2985517b
dashboard link: https://syzkaller.appspot.com/bug?extid=ecf51a7ccb6b1394e90c
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1732d8ce580000

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in blk_update_request

==================================================================
BUG: KASAN: slab-use-after-free in __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
BUG: KASAN: slab-use-after-free in _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166
Read of size 1 at addr ffff888029ea23a8 by task syz-execprog/6206

CPU: 1 UID: 0 PID: 6206 Comm: syz-execprog Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 __kasan_check_byte+0x2a/0x40 mm/kasan/common.c:574
 kasan_check_byte include/linux/kasan.h:402 [inline]
 lock_acquire+0x84/0x350 kernel/locking/lockdep.c:5842
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:132 [inline]
 _raw_spin_lock_irqsave+0x40/0x60 kernel/locking/spinlock.c:166
 rtlock_slowlock kernel/locking/rtmutex.c:1910 [inline]
 rtlock_lock kernel/locking/spinlock_rt.c:43 [inline]
 __rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline]
 rt_spin_lock+0x157/0x400 kernel/locking/spinlock_rt.c:57
 spin_lock include/linux/spinlock_rt.h:45 [inline]
 __wake_up_common_lock+0x2f/0x1e0 kernel/sched/wait.c:124
 blk_update_request+0x57e/0xe60 block/blk-mq.c:1016
 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1178
 blk_complete_reqs block/blk-mq.c:1253 [inline]
 blk_done_softirq+0x10a/0x160 block/blk-mq.c:1258
 handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 __local_bh_enable_ip+0x170/0x2b0 kernel/softirq.c:302
 lock_sock include/net/sock.h:1713 [inline]
 tcp_recvmsg+0xdb/0x530 net/ipv4/tcp.c:2947
 sock_recvmsg_nosec net/socket.c:1137 [inline]
 sock_recvmsg+0xfa/0x1b0 net/socket.c:1159
 sock_read_iter+0x25a/0x330 net/socket.c:1229
 new_sync_read fs/read_write.c:493 [inline]
 vfs_read+0x58b/0xa80 fs/read_write.c:574
 ksys_read+0x156/0x270 fs/read_write.c:717
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x40d3ce
Code: ff cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc 49 89 f2 48 89 fa 48 89 ce 48 89 df 0f 05 <48> 3d 01 f0 ff ff 76 15 48 f7 d8 48 89 c1 48 c7 c0 ff ff ff ff 48
RSP: 002b:00002b0cf6eef3d8 EFLAGS: 00000202 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 000000000040d3ce
RDX: 0000000001e71274 RSI: 00002b0cf7180000 RDI: 0000000000000006
RBP: 00002b0cf6eef418 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00007ffed587ed60
R13: 0000000000000001 R14: 00002b0cf6d672c0 R15: 0000000000000001
 </TASK>

Allocated by task 6803:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x3a6/0x690 mm/slub.c:5415
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 open_inline_log fs/jfs/jfs_logmgr.c:1157 [inline]
 lmLogOpen+0x2d1/0xfa0 fs/jfs/jfs_logmgr.c:1067
 jfs_mount_rw+0xee/0x670 fs/jfs/jfs_mount.c:257
 jfs_fill_super+0x754/0xd80 fs/jfs/super.c:532
 get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694
 vfs_get_tree+0x92/0x2a0 fs/super.c:1754
 fc_mount fs/namespace.c:1193 [inline]
 do_new_mount_fc fs/namespace.c:3758 [inline]
 do_new_mount+0x341/0xd30 fs/namespace.c:3834
 do_mount fs/namespace.c:4167 [inline]
 __do_sys_mount fs/namespace.c:4383 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4360
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 6544:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2689 [inline]
 slab_free mm/slub.c:6246 [inline]
 kfree+0x1c5/0x6c0 mm/slub.c:6561
 lmLogClose+0x297/0x520 fs/jfs/jfs_logmgr.c:-1
 jfs_umount+0x2fb/0x3d0 fs/jfs/jfs_umount.c:124
 jfs_put_super+0x8c/0x190 fs/jfs/super.c:194
 generic_shutdown_super+0x13d/0x2d0 fs/super.c:646
 kill_block_super+0x44/0x90 fs/super.c:1725
 deactivate_locked_super+0xbc/0x130 fs/super.c:476
 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline]
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888029ea2000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 936 bytes inside of
 freed 2048-byte region [ffff888029ea2000, ffff888029ea2800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888029ea1000 pfn:0x29ea0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000240(workingset|head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000240 ffff88801a01f000 ffffea0000e8dc10 ffffea0000cb5810
raw: ffff888029ea1000 0000000800080006 00000000f5000000 0000000000000000
head: 0080000000000240 ffff88801a01f000 ffffea0000e8dc10 ffffea0000cb5810
head: ffff888029ea1000 0000000800080006 00000000f5000000 0000000000000000
head: 0080000000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd28c0(GFP_NOWAIT|__GFP_IO|__GFP_FS|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 3872, tgid 3872 (kworker/u8:15), ts 89329858437, free_ts 89297441219
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1860
 prep_new_page mm/page_alloc.c:1868 [inline]
 get_page_from_freelist+0x27c8/0x2840 mm/page_alloc.c:3948
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5228
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x33c/0x3d0 mm/slub.c:7251
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x373/0x720 mm/slub.c:4651
 alloc_from_pcs mm/slub.c:4749 [inline]
 slab_alloc_node mm/slub.c:4883 [inline]
 __do_kmalloc_node mm/slub.c:5294 [inline]
 __kmalloc_node_track_caller_noprof+0x60b/0x7e0 mm/slub.c:5403
 kmalloc_reserve net/core/skbuff.c:635 [inline]
 pskb_expand_head+0x230/0x1390 net/core/skbuff.c:2302
 netlink_trim+0x1b3/0x2c0 net/netlink/af_netlink.c:1299
 netlink_broadcast_filtered+0x80/0xea0 net/netlink/af_netlink.c:1512
 nlmsg_multicast_filtered include/net/netlink.h:1165 [inline]
 nlmsg_multicast include/net/netlink.h:1184 [inline]
 nlmsg_notify+0xf0/0x1a0 net/netlink/af_netlink.c:2593
 netif_state_change+0x297/0x3a0 net/core/dev.c:1605
 __linkwatch_run_queue+0x575/0x850 net/core/link_watch.c:240
 linkwatch_event+0x4c/0x60 net/core/link_watch.c:314
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
page last free pid 5861 tgid 5861 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1404 [inline]
 __free_frozen_pages+0xfa6/0x10f0 mm/page_alloc.c:2945
 __slab_free+0x252/0x2a0 mm/slub.c:5608
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4569 [inline]
 slab_alloc_node mm/slub.c:4898 [inline]
 kmem_cache_alloc_lru_noprof+0x33c/0x680 mm/slub.c:4917
 sock_alloc_inode+0x2c/0x190 net/socket.c:328
 alloc_inode+0x6a/0x1b0 fs/inode.c:345
 new_inode_pseudo include/linux/fs.h:3022 [inline]
 sock_alloc net/socket.c:697 [inline]
 __sock_create+0x12d/0x9d0 net/socket.c:1628
 sock_create net/socket.c:1722 [inline]
 __sys_socket_create net/socket.c:1759 [inline]
 __sys_socket+0xd6/0x1b0 net/socket.c:1806
 __do_sys_socket net/socket.c:1820 [inline]
 __se_sys_socket net/socket.c:1818 [inline]
 __x64_sys_socket+0x7a/0x90 net/socket.c:1818
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff888029ea2280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888029ea2300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888029ea2380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff888029ea2400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888029ea2480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit:         43cfbdda Merge tag 'for-linus-iommufd' of git://git.ke..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=16d3f036580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4660d1ff2985517b
dashboard link: https://syzkaller.appspot.com/bug?extid=ecf51a7ccb6b1394e90c
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=11c4a4ce580000

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in rtlock_slowlock_locked

==================================================================
BUG: KASAN: slab-use-after-free in __raw_spin_lock_irq include/linux/spinlock_api_smp.h:142 [inline]
BUG: KASAN: slab-use-after-free in _raw_spin_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:174
Read of size 1 at addr ffff8880391af3a8 by task ksoftirqd/1/30

CPU: 1 UID: 0 PID: 30 Comm: ksoftirqd/1 Not tainted syzkaller #0 PREEMPT_{RT,(full)} 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 print_address_description+0x55/0x1e0 mm/kasan/report.c:378
 print_report+0x58/0x70 mm/kasan/report.c:482
 kasan_report+0x117/0x150 mm/kasan/report.c:595
 __kasan_check_byte+0x2a/0x40 mm/kasan/common.c:574
 kasan_check_byte include/linux/kasan.h:402 [inline]
 lock_acquire+0x84/0x350 kernel/locking/lockdep.c:5842
 __raw_spin_lock_irq include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock_irq+0x3d/0x50 kernel/locking/spinlock.c:174
 rtlock_slowlock_locked+0x3640/0x3c80 kernel/locking/rtmutex.c:1887
 rtlock_slowlock kernel/locking/rtmutex.c:1911 [inline]
 rtlock_lock kernel/locking/spinlock_rt.c:43 [inline]
 __rt_spin_lock kernel/locking/spinlock_rt.c:49 [inline]
 rt_spin_lock+0x165/0x400 kernel/locking/spinlock_rt.c:57
 spin_lock include/linux/spinlock_rt.h:45 [inline]
 __wake_up_common_lock+0x2f/0x1e0 kernel/sched/wait.c:124
 blk_update_request+0x57e/0xe60 block/blk-mq.c:1016
 blk_mq_end_request+0x3e/0x70 block/blk-mq.c:1178
 blk_complete_reqs block/blk-mq.c:1253 [inline]
 blk_done_softirq+0x10a/0x160 block/blk-mq.c:1258
 handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622
 run_ksoftirqd+0x52/0x180 kernel/softirq.c:1076
 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Allocated by task 7581:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __kmalloc_cache_noprof+0x3a6/0x690 mm/slub.c:5415
 kmalloc_noprof include/linux/slab.h:950 [inline]
 kzalloc_noprof include/linux/slab.h:1188 [inline]
 open_inline_log fs/jfs/jfs_logmgr.c:1157 [inline]
 lmLogOpen+0x2d1/0xfa0 fs/jfs/jfs_logmgr.c:1067
 jfs_mount_rw+0xee/0x670 fs/jfs/jfs_mount.c:257
 jfs_fill_super+0x754/0xd80 fs/jfs/super.c:532
 get_tree_bdev_flags+0x431/0x4f0 fs/super.c:1694
 vfs_get_tree+0x92/0x2a0 fs/super.c:1754
 fc_mount fs/namespace.c:1193 [inline]
 do_new_mount_fc fs/namespace.c:3758 [inline]
 do_new_mount+0x341/0xd30 fs/namespace.c:3834
 do_mount fs/namespace.c:4167 [inline]
 __do_sys_mount fs/namespace.c:4383 [inline]
 __se_sys_mount+0x31d/0x420 fs/namespace.c:4360
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x15f/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 6578:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:584
 poison_slab_object mm/kasan/common.c:253 [inline]
 __kasan_slab_free+0x5c/0x80 mm/kasan/common.c:285
 kasan_slab_free include/linux/kasan.h:235 [inline]
 slab_free_hook mm/slub.c:2689 [inline]
 slab_free mm/slub.c:6246 [inline]
 kfree+0x1c5/0x6c0 mm/slub.c:6561
 lmLogClose+0x297/0x520 fs/jfs/jfs_logmgr.c:-1
 jfs_umount+0x2fb/0x3d0 fs/jfs/jfs_umount.c:124
 jfs_put_super+0x8c/0x190 fs/jfs/super.c:194
 generic_shutdown_super+0x13d/0x2d0 fs/super.c:646
 kill_block_super+0x44/0x90 fs/super.c:1725
 deactivate_locked_super+0xbc/0x130 fs/super.c:476
 cleanup_mnt+0x437/0x4d0 fs/namespace.c:1312
 task_work_run+0x1d9/0x270 kernel/task_work.c:233
 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
 __exit_to_user_mode_loop kernel/entry/common.c:67 [inline]
 exit_to_user_mode_loop+0xed/0x480 kernel/entry/common.c:98
 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline]
 syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:238 [inline]
 syscall_exit_to_user_mode include/linux/entry-common.h:328 [inline]
 do_syscall_64+0x33e/0xf80 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8880391af000
 which belongs to the cache kmalloc-2k of size 2048
The buggy address is located 936 bytes inside of
 freed 2048-byte region [ffff8880391af000, ffff8880391af800)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff8880391a8000 pfn:0x391a8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x80000000000240(workingset|head|node=0|zone=1)
page_type: f5(slab)
raw: 0080000000000240 ffff88801a01f000 ffffea000081f610 ffffea0000ad4010
raw: ffff8880391a8000 0000000800080006 00000000f5000000 0000000000000000
head: 0080000000000240 ffff88801a01f000 ffffea000081f610 ffffea0000ad4010
head: ffff8880391a8000 0000000800080006 00000000f5000000 0000000000000000
head: 0080000000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff
head: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000008
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1246, tgid 1246 (kworker/0:3), ts 92650036638, free_ts 65245208477
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x231/0x280 mm/page_alloc.c:1860
 prep_new_page mm/page_alloc.c:1868 [inline]
 get_page_from_freelist+0x27c8/0x2840 mm/page_alloc.c:3948
 __alloc_frozen_pages_noprof+0x18d/0x380 mm/page_alloc.c:5228
 alloc_slab_page mm/slub.c:3278 [inline]
 allocate_slab+0x77/0x660 mm/slub.c:3467
 new_slab mm/slub.c:3525 [inline]
 refill_objects+0x33c/0x3d0 mm/slub.c:7251
 refill_sheaf mm/slub.c:2816 [inline]
 __pcs_replace_empty_main+0x373/0x720 mm/slub.c:4651
 alloc_from_pcs mm/slub.c:4749 [inline]
 slab_alloc_node mm/slub.c:4883 [inline]
 __do_kmalloc_node mm/slub.c:5294 [inline]
 __kmalloc_node_track_caller_noprof+0x60b/0x7e0 mm/slub.c:5403
 kmalloc_reserve net/core/skbuff.c:635 [inline]
 __alloc_skb+0x2c1/0x7d0 net/core/skbuff.c:713
 alloc_skb include/linux/skbuff.h:1383 [inline]
 mld_newpack+0x14c/0xc90 net/ipv6/mcast.c:1775
 add_grhead+0x5a/0x2a0 net/ipv6/mcast.c:1886
 add_grec+0x1452/0x1740 net/ipv6/mcast.c:2025
 mld_send_cr net/ipv6/mcast.c:2148 [inline]
 mld_ifc_work+0x6e6/0xe70 net/ipv6/mcast.c:2693
 process_one_work kernel/workqueue.c:3302 [inline]
 process_scheduled_works+0xb5d/0x1860 kernel/workqueue.c:3385
 worker_thread+0xa53/0xfc0 kernel/workqueue.c:3466
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
page last free pid 5740 tgid 5740 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 __free_pages_prepare mm/page_alloc.c:1404 [inline]
 __free_frozen_pages+0xfa6/0x10f0 mm/page_alloc.c:2945
 __slab_free+0x252/0x2a0 mm/slub.c:5608
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x99/0x100 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x148/0x160 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x22/0x80 mm/kasan/common.c:350
 kasan_slab_alloc include/linux/kasan.h:253 [inline]
 slab_post_alloc_hook mm/slub.c:4569 [inline]
 slab_alloc_node mm/slub.c:4898 [inline]
 kmem_cache_alloc_noprof+0x33b/0x680 mm/slub.c:4905
 mt_alloc_one lib/maple_tree.c:139 [inline]
 mas_alloc_nodes+0x291/0x350 lib/maple_tree.c:1089
 mas_preallocate+0x2d6/0x640 lib/maple_tree.c:4961
 vma_iter_prealloc mm/vma.h:577 [inline]
 commit_merge+0x21a/0x660 mm/vma.c:754
 vma_expand+0x87d/0xfa0 mm/vma.c:1219
 relocate_vma_down+0x375/0x590 mm/vma_exec.c:59
 setup_arg_pages+0x70a/0xbd0 fs/exec.c:690
 load_elf_binary+0xc67/0x29b0 fs/binfmt_elf.c:1028
 search_binary_handler fs/exec.c:1664 [inline]
 exec_binprm fs/exec.c:1696 [inline]
 bprm_execve+0x94a/0x1440 fs/exec.c:1748
 do_execveat_common+0x50d/0x690 fs/exec.c:1846
 __do_sys_execve fs/exec.c:1930 [inline]
 __se_sys_execve fs/exec.c:1924 [inline]
 __x64_sys_execve+0x97/0xc0 fs/exec.c:1924

Memory state around the buggy address:
 ffff8880391af280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880391af300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880391af380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff8880391af400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880391af480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit:         d662a710 Merge tag 'dmaengine-7.1-rc1' of git://git.ke..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=146541ba580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=26671aec07bf6cc
dashboard link: https://syzkaller.appspot.com/bug?extid=ecf51a7ccb6b1394e90c
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=12e24702580000

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+ecf51a7ccb6b1394e90c@syzkaller.appspotmail.com
Tested-by: syzbot+ecf51a7ccb6b1394e90c@syzkaller.appspotmail.com

Tested on:

commit:         59bd5ae0 Merge tag 'for-v7.1' of git://git.kernel.org/..
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=17748fca580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=b44c9b54cc2c4033
dashboard link: https://syzkaller.appspot.com/bug?extid=ecf51a7ccb6b1394e90c
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=17864702580000

Note: testing is done by a robot and is best-effort only.

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[Edward Adam Davis]

#syz test: upstream master

diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index 5f31c12f4607..69b9d161b783 100644
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -1984,7 +1984,7 @@ static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp)
 		submit_bio(bio);
 	}
 
-	wait_event(bp->l_ioevent, (bp->l_flag == lbmDONE));
+	wait_event(bp->l_ioevent, (bp->l_flag & lbmDONE));
 
 	return 0;
 }

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[Edward Adam Davis]

#syz test: upstream master

diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index 5f31c12f4607..f795f19d24bb 100644
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -1984,7 +1984,7 @@ static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp)
 		submit_bio(bio);
 	}
 
-	wait_event(bp->l_ioevent, (bp->l_flag == lbmDONE));
+	wait_event(bp->l_ioevent, (bp->l_flag & lbmDONE));
 
 	return 0;
 }
@@ -2192,11 +2192,6 @@ static void lbmIODone(struct bio *bio)
 	if (bp->l_flag & lbmREAD) {
 		bp->l_flag &= ~lbmREAD;
 
-		LCACHE_UNLOCK(flags);
-		/* wakeup I/O initiator */
-		LCACHE_WAKEUP(&bp->l_ioevent);
-		LCACHE_LOCK(flags);		/* disable+lock */
-
 		goto out;
 	}
 
@@ -2219,10 +2214,8 @@ static void lbmIODone(struct bio *bio)
 	log = bp->l_log;
 	log->clsn = (bp->l_pn << L2LOGPSIZE) + bp->l_ceor;
 
-	if (bp->l_flag & lbmDIRECT) {
-		LCACHE_WAKEUP(&bp->l_ioevent);
+	if (bp->l_flag & lbmDIRECT)
 		goto out;
-	}
 
 	tail = log->wqueue;
 
@@ -2273,10 +2266,7 @@ static void lbmIODone(struct bio *bio)
 	 * leave buffer for i/o initiator to dispose
 	 */
 	if (bp->l_flag & lbmSYNC) {
-		LCACHE_UNLOCK(flags);
-		/* wakeup I/O initiator */
-		LCACHE_WAKEUP(&bp->l_ioevent);
-		LCACHE_LOCK(flags);		/* disable+lock */
+		goto out;
 	}
 
 	/*
@@ -2302,6 +2292,8 @@ static void lbmIODone(struct bio *bio)
 
 out:
 	bp->l_flag |= lbmDONE;
+	/* wakeup I/O initiator */
+	LCACHE_WAKEUP(&bp->l_ioevent);
 	LCACHE_UNLOCK(flags);
 }
 

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

failed to apply patch:
checking file fs/jfs/jfs_logmgr.c
Hunk #1 FAILED at 1984.
1 out of 1 hunk FAILED



Tested on:

commit:         8541d8f7 Merge tag 'mtd/for-7.1' of git://git.kernel.o..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=4660d1ff2985517b
dashboard link: https://syzkaller.appspot.com/bug?extid=ecf51a7ccb6b1394e90c
compiler:       
patch:          https://syzkaller.appspot.com/x/patch.diff?x=16580836580000

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[Edward Adam Davis]

#syz test

diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index 5f31c12f4607..f795f19d24bb 100644
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -1984,7 +1984,7 @@ static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp)
 		submit_bio(bio);
 	}
 
-	wait_event(bp->l_ioevent, (bp->l_flag == lbmDONE));
+	wait_event(bp->l_ioevent, (bp->l_flag & lbmDONE));
 
 	return 0;
 }
@@ -2192,11 +2192,6 @@ static void lbmIODone(struct bio *bio)
 	if (bp->l_flag & lbmREAD) {
 		bp->l_flag &= ~lbmREAD;
 
-		LCACHE_UNLOCK(flags);
-		/* wakeup I/O initiator */
-		LCACHE_WAKEUP(&bp->l_ioevent);
-		LCACHE_LOCK(flags);		/* disable+lock */
-
 		goto out;
 	}
 
@@ -2219,10 +2214,8 @@ static void lbmIODone(struct bio *bio)
 	log = bp->l_log;
 	log->clsn = (bp->l_pn << L2LOGPSIZE) + bp->l_ceor;
 
-	if (bp->l_flag & lbmDIRECT) {
-		LCACHE_WAKEUP(&bp->l_ioevent);
+	if (bp->l_flag & lbmDIRECT)
 		goto out;
-	}
 
 	tail = log->wqueue;
 
@@ -2273,10 +2266,7 @@ static void lbmIODone(struct bio *bio)
 	 * leave buffer for i/o initiator to dispose
 	 */
 	if (bp->l_flag & lbmSYNC) {
-		LCACHE_UNLOCK(flags);
-		/* wakeup I/O initiator */
-		LCACHE_WAKEUP(&bp->l_ioevent);
-		LCACHE_LOCK(flags);		/* disable+lock */
+		goto out;
 	}
 
 	/*
@@ -2302,6 +2292,8 @@ static void lbmIODone(struct bio *bio)
 
 out:
 	bp->l_flag |= lbmDONE;
+	/* wakeup I/O initiator */
+	LCACHE_WAKEUP(&bp->l_ioevent);
 	LCACHE_UNLOCK(flags);
 }
 

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

failed to apply patch:
checking file fs/jfs/jfs_logmgr.c
Hunk #1 FAILED at 1984.
Hunk #2 FAILED at 2192.
Hunk #3 succeeded at 2217 (offset -2 lines).
Hunk #4 FAILED at 2271.
Hunk #5 succeeded at 2296 (offset -4 lines).
3 out of 5 hunks FAILED



Tested on:

commit:         8541d8f7 Merge tag 'mtd/for-7.1' of git://git.kernel.o..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=4660d1ff2985517b
dashboard link: https://syzkaller.appspot.com/bug?extid=ecf51a7ccb6b1394e90c
compiler:       
patch:          https://syzkaller.appspot.com/x/patch.diff?x=16f80836580000

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[Edward Adam Davis]

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master

diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index 5f31c12f4607..f795f19d24bb 100644
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -1984,7 +1984,7 @@ static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp)
 		submit_bio(bio);
 	}
 
-	wait_event(bp->l_ioevent, (bp->l_flag == lbmDONE));
+	wait_event(bp->l_ioevent, (bp->l_flag & lbmDONE));
 
 	return 0;
 }
@@ -2192,11 +2192,6 @@ static void lbmIODone(struct bio *bio)
 	if (bp->l_flag & lbmREAD) {
 		bp->l_flag &= ~lbmREAD;
 
-		LCACHE_UNLOCK(flags);
-		/* wakeup I/O initiator */
-		LCACHE_WAKEUP(&bp->l_ioevent);
-		LCACHE_LOCK(flags);		/* disable+lock */
-
 		goto out;
 	}
 
@@ -2219,10 +2214,8 @@ static void lbmIODone(struct bio *bio)
 	log = bp->l_log;
 	log->clsn = (bp->l_pn << L2LOGPSIZE) + bp->l_ceor;
 
-	if (bp->l_flag & lbmDIRECT) {
-		LCACHE_WAKEUP(&bp->l_ioevent);
+	if (bp->l_flag & lbmDIRECT)
 		goto out;
-	}
 
 	tail = log->wqueue;
 
@@ -2273,10 +2266,7 @@ static void lbmIODone(struct bio *bio)
 	 * leave buffer for i/o initiator to dispose
 	 */
 	if (bp->l_flag & lbmSYNC) {
-		LCACHE_UNLOCK(flags);
-		/* wakeup I/O initiator */
-		LCACHE_WAKEUP(&bp->l_ioevent);
-		LCACHE_LOCK(flags);		/* disable+lock */
+		goto out;
 	}
 
 	/*
@@ -2302,6 +2292,8 @@ static void lbmIODone(struct bio *bio)
 
 out:
 	bp->l_flag |= lbmDONE;
+	/* wakeup I/O initiator */
+	LCACHE_WAKEUP(&bp->l_ioevent);
 	LCACHE_UNLOCK(flags);
 }
 

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

failed to apply patch:
checking file fs/jfs/jfs_logmgr.c
Hunk #1 FAILED at 1984.
Hunk #2 FAILED at 2192.
Hunk #3 succeeded at 2217 (offset -2 lines).
Hunk #4 FAILED at 2271.
Hunk #5 succeeded at 2296 (offset -4 lines).
3 out of 5 hunks FAILED



Tested on:

commit:         8541d8f7 Merge tag 'mtd/for-7.1' of git://git.kernel.o..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=4660d1ff2985517b
dashboard link: https://syzkaller.appspot.com/bug?extid=ecf51a7ccb6b1394e90c
compiler:       
patch:          https://syzkaller.appspot.com/x/patch.diff?x=108f24ce580000

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[Edward Adam Davis]

#syz test: upstream master

diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index ada00d5bc214..729baf49a048 100644
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -1986,7 +1986,7 @@ static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp)
 		submit_bio(bio);
 	}
 
-	wait_event(bp->l_ioevent, (bp->l_flag != lbmREAD));
+	wait_event(bp->l_ioevent, (bp->l_flag & lbmDONE));
 
 	return 0;
 }
@@ -2180,7 +2180,6 @@ static void lbmIODone(struct bio *bio)
 
 	LCACHE_LOCK(flags);		/* disable+lock */
 
-	bp->l_flag |= lbmDONE;
 
 	if (bio->bi_status) {
 		bp->l_flag |= lbmERROR;
@@ -2196,12 +2195,7 @@ static void lbmIODone(struct bio *bio)
 	if (bp->l_flag & lbmREAD) {
 		bp->l_flag &= ~lbmREAD;
 
-		LCACHE_UNLOCK(flags);	/* unlock+enable */
-
-		/* wakeup I/O initiator */
-		LCACHE_WAKEUP(&bp->l_ioevent);
-
-		return;
+		goto out;
 	}
 
 	/*
@@ -2224,9 +2218,7 @@ static void lbmIODone(struct bio *bio)
 	log->clsn = (bp->l_pn << L2LOGPSIZE) + bp->l_ceor;
 
 	if (bp->l_flag & lbmDIRECT) {
-		LCACHE_WAKEUP(&bp->l_ioevent);
-		LCACHE_UNLOCK(flags);
-		return;
+		goto out;
 	}
 
 	tail = log->wqueue;
@@ -2278,10 +2270,7 @@ static void lbmIODone(struct bio *bio)
 	 * leave buffer for i/o initiator to dispose
 	 */
 	if (bp->l_flag & lbmSYNC) {
-		LCACHE_UNLOCK(flags);	/* unlock+enable */
-
-		/* wakeup I/O initiator */
-		LCACHE_WAKEUP(&bp->l_ioevent);
+		goto out;
 	}
 
 	/*
@@ -2290,6 +2279,7 @@ static void lbmIODone(struct bio *bio)
 	else if (bp->l_flag & lbmGC) {
 		LCACHE_UNLOCK(flags);
 		lmPostGC(bp);
+		LCACHE_LOCK(flags);		/* disable+lock */
 	}
 
 	/*
@@ -2302,9 +2292,12 @@ static void lbmIODone(struct bio *bio)
 		assert(bp->l_flag & lbmRELEASE);
 		assert(bp->l_flag & lbmFREE);
 		lbmfree(bp);
-
-		LCACHE_UNLOCK(flags);	/* unlock+enable */
 	}
+out:
+	bp->l_flag |= lbmDONE;
+	/* wakeup I/O initiator */
+	LCACHE_WAKEUP(&bp->l_ioevent);
+	LCACHE_UNLOCK(flags);	/* unlock+enable */
 }
 
 int jfsIOWait(void *arg)

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

failed to apply patch:
checking file fs/jfs/jfs_logmgr.c
Hunk #1 FAILED at 1984.
Hunk #2 FAILED at 2192.
Hunk #3 succeeded at 2217 (offset -2 lines).
Hunk #4 FAILED at 2271.
Hunk #5 succeeded at 2296 (offset -4 lines).
3 out of 5 hunks FAILED



Tested on:

commit:         c7275b05 Add linux-next specific files for 20260417
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
kernel config:  https://syzkaller.appspot.com/x/.config?x=4660d1ff2985517b
dashboard link: https://syzkaller.appspot.com/bug?extid=ecf51a7ccb6b1394e90c
compiler:       
patch:          https://syzkaller.appspot.com/x/patch.diff?x=174f24ce580000

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[Edward Adam Davis]

#syz test https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master

diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index 306165e61438..f795f19d24bb 100644
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -1984,7 +1984,7 @@ static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp)
 		submit_bio(bio);
 	}
 
-	wait_event(bp->l_ioevent, (bp->l_flag != lbmREAD));
+	wait_event(bp->l_ioevent, (bp->l_flag & lbmDONE));
 
 	return 0;
 }
@@ -2192,9 +2192,6 @@ static void lbmIODone(struct bio *bio)
 	if (bp->l_flag & lbmREAD) {
 		bp->l_flag &= ~lbmREAD;
 
-		/* wakeup I/O initiator */
-		LCACHE_WAKEUP(&bp->l_ioevent);
-
 		goto out;
 	}
 
@@ -2217,10 +2214,8 @@ static void lbmIODone(struct bio *bio)
 	log = bp->l_log;
 	log->clsn = (bp->l_pn << L2LOGPSIZE) + bp->l_ceor;
 
-	if (bp->l_flag & lbmDIRECT) {
-		LCACHE_WAKEUP(&bp->l_ioevent);
+	if (bp->l_flag & lbmDIRECT)
 		goto out;
-	}
 
 	tail = log->wqueue;
 
@@ -2271,8 +2266,7 @@ static void lbmIODone(struct bio *bio)
 	 * leave buffer for i/o initiator to dispose
 	 */
 	if (bp->l_flag & lbmSYNC) {
-		/* wakeup I/O initiator */
-		LCACHE_WAKEUP(&bp->l_ioevent);
+		goto out;
 	}
 
 	/*
@@ -2298,6 +2292,8 @@ static void lbmIODone(struct bio *bio)
 
 out:
 	bp->l_flag |= lbmDONE;
+	/* wakeup I/O initiator */
+	LCACHE_WAKEUP(&bp->l_ioevent);
 	LCACHE_UNLOCK(flags);
 }
 

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[syzbot]

Hello,

syzbot tried to test the proposed patch but the build/boot failed:

failed to apply patch:
checking file fs/jfs/jfs_logmgr.c
Hunk #1 succeeded at 1984 (offset -2 lines).
Hunk #2 FAILED at 2180.
Hunk #3 FAILED at 2196.
Hunk #4 FAILED at 2224.
Hunk #5 FAILED at 2278.
Hunk #6 FAILED at 2290.
Hunk #7 FAILED at 2302.
6 out of 7 hunks FAILED



Tested on:

commit:         8541d8f7 Merge tag 'mtd/for-7.1' of git://git.kernel.o..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=4660d1ff2985517b
dashboard link: https://syzkaller.appspot.com/bug?extid=ecf51a7ccb6b1394e90c
compiler:       
patch:          https://syzkaller.appspot.com/x/patch.diff?x=142f24ce580000

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+ecf51a7ccb6b1394e90c@syzkaller.appspotmail.com
Tested-by: syzbot+ecf51a7ccb6b1394e90c@syzkaller.appspotmail.com

Tested on:

commit:         c7275b05 Add linux-next specific files for 20260417
git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git master
console output: https://syzkaller.appspot.com/x/log.txt?x=145842d2580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=8d583ddcf2981d2a
dashboard link: https://syzkaller.appspot.com/bug?extid=ecf51a7ccb6b1394e90c
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=1604c1ba580000

Note: testing is done by a robot and is best-effort only.

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[Edward Adam Davis]

#syz test: upstream master

diff --git a/fs/jfs/jfs_logmgr.c b/fs/jfs/jfs_logmgr.c
index 306165e61438..cbe3878ff886 100644
--- a/fs/jfs/jfs_logmgr.c
+++ b/fs/jfs/jfs_logmgr.c
@@ -1984,7 +1984,7 @@ static int lbmRead(struct jfs_log * log, int pn, struct lbuf ** bpp)
 		submit_bio(bio);
 	}
 
-	wait_event(bp->l_ioevent, (bp->l_flag != lbmREAD));
+	wait_event(bp->l_ioevent, (bp->l_flag & lbmDONE));
 
 	return 0;
 }
@@ -2192,9 +2192,6 @@ static void lbmIODone(struct bio *bio)
 	if (bp->l_flag & lbmREAD) {
 		bp->l_flag &= ~lbmREAD;
 
-		/* wakeup I/O initiator */
-		LCACHE_WAKEUP(&bp->l_ioevent);
-
 		goto out;
 	}
 
@@ -2218,7 +2215,6 @@ static void lbmIODone(struct bio *bio)
 	log->clsn = (bp->l_pn << L2LOGPSIZE) + bp->l_ceor;
 
 	if (bp->l_flag & lbmDIRECT) {
-		LCACHE_WAKEUP(&bp->l_ioevent);
 		goto out;
 	}
 
@@ -2271,8 +2267,7 @@ static void lbmIODone(struct bio *bio)
 	 * leave buffer for i/o initiator to dispose
 	 */
 	if (bp->l_flag & lbmSYNC) {
-		/* wakeup I/O initiator */
-		LCACHE_WAKEUP(&bp->l_ioevent);
+		goto out;
 	}
 
 	/*
@@ -2298,6 +2293,8 @@ static void lbmIODone(struct bio *bio)
 
 out:
 	bp->l_flag |= lbmDONE;
+	/* wakeup I/O initiator */
+	LCACHE_WAKEUP(&bp->l_ioevent);
 	LCACHE_UNLOCK(flags);
 }
 

Re: [syzbot] [jfs?] KASAN: slab-use-after-free Read in lbmIODone

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+ecf51a7ccb6b1394e90c@syzkaller.appspotmail.com
Tested-by: syzbot+ecf51a7ccb6b1394e90c@syzkaller.appspotmail.com

Tested on:

commit:         8541d8f7 Merge tag 'mtd/for-7.1' of git://git.kernel.o..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=12a8a4ce580000
kernel config:  https://syzkaller.appspot.com/x/.config?x=ecb532db4f89a3a6
dashboard link: https://syzkaller.appspot.com/bug?extid=ecf51a7ccb6b1394e90c
compiler:       Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8
patch:          https://syzkaller.appspot.com/x/patch.diff?x=14936f16580000

Note: testing is done by a robot and is best-effort only.