From: syzbot <syzbot+88ffc513fdcbbb39cdf7@syzkaller.appspotmail.com>
To: agruenba@redhat.com, gfs2@lists.linux.dev,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
Subject: [syzbot] [gfs2?] KASAN: slab-use-after-free Read in gfs2_withdraw_func (2)
Date: Thu, 08 Oct 2026 17:58:26 -0700 [thread overview]
Message-ID: <6ac83c32.bbc4c7f9.15faa7.0008.GAE@google.com> (raw)
Hello,
syzbot found the following issue on:
HEAD commit: a74306e2e676 Merge tag 'clk-fixes-for-linus-v7.3' of git:/..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16328835580000
kernel config: https://syzkaller.appspot.com/x/.config?x=66e2e48805cd3a64
dashboard link: https://syzkaller.appspot.com/bug?extid=88ffc513fdcbbb39cdf7
compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-a74306e2.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ceef0db30e25/vmlinux-a74306e2.xz
kernel image: https://storage.googleapis.com/syzbot-assets/cfca6997ed38/bzImage-a74306e2.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+88ffc513fdcbbb39cdf7@syzkaller.appspotmail.com
gfs2: fsid=syz:syz.0: jid=0, already locked for use
gfs2: fsid=syz:syz.0: jid=0: Looking at journal...
gfs2: fsid=syz:syz.0: jid=0: Journal head lookup took 101ms
gfs2: fsid=syz:syz.0: jid=0: Done
==================================================================
BUG: KASAN: slab-use-after-free in gfs2_withdraw_func+0x42/0x440 fs/gfs2/util.c:208
Read of size 8 at addr ffff888034454348 by task kworker/0:0/9
CPU: 0 UID: 0 PID: 9 Comm: kworker/0:0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Workqueue: events gfs2_withdraw_func
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
gfs2_withdraw_func+0x42/0x440 fs/gfs2/util.c:208
process_one_work kernel/workqueue.c:3396 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
kthread+0x38b/0x480 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 5332:
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:409 [inline]
__kasan_kmalloc+0x93/0xb0 mm/kasan/common.c:426
kasan_kmalloc include/linux/kasan.h:263 [inline]
__kmalloc_cache_noprof+0x321/0x600 mm/slub.c:5563
_kmalloc_noprof include/linux/slab.h:991 [inline]
_kzalloc_noprof include/linux/slab.h:1312 [inline]
init_sbd fs/gfs2/ops_fstype.c:79 [inline]
gfs2_fill_super+0x125/0x20d0 fs/gfs2/ops_fstype.c:1123
get_tree_bdev_flags+0x430/0x4f0 fs/super.c:1872
gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1333
vfs_get_tree+0x92/0x2a0 fs/super.c:1932
fc_mount fs/namespace.c:1198 [inline]
do_new_mount_fc fs/namespace.c:3772 [inline]
do_new_mount+0x319/0xdc0 fs/namespace.c:3848
do_mount fs/namespace.c:4181 [inline]
__do_sys_mount fs/namespace.c:4397 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4374
do_syscall_x64 arch/x86/entry/syscall_64.c:61 [inline]
do_syscall_64+0x166/0x520 arch/x86/entry/syscall_64.c:84
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Freed by task 5332:
kasan_save_stack mm/kasan/common.c:57 [inline]
kasan_save_track+0x3e/0x80 mm/kasan/common.c:78
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:584
poison_slab_object mm/kasan/common.c:264 [inline]
__kasan_slab_free+0x5c/0x80 mm/kasan/common.c:296
kasan_slab_free include/linux/kasan.h:235 [inline]
slab_free_hook mm/slub.c:2748 [inline]
slab_free mm/slub.c:6509 [inline]
kfree+0x1c5/0x650 mm/slub.c:6802
generic_shutdown_super+0x13d/0x2d0 fs/super.c:751
kill_block_super+0x44/0xa0 fs/super.c:1903
deactivate_locked_super+0xbe/0x110 fs/super.c:586
cleanup_mnt+0x3d3/0x460 fs/namespace.c:1317
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:70 [inline]
exit_to_user_mode_loop+0x204/0x770 kernel/entry/common.c:101
__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:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline]
do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
Last potentially related work creation:
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:57
kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:556
insert_work+0x3d/0x330 kernel/workqueue.c:2272
__queue_work+0xd07/0x10d0 kernel/workqueue.c:2448
queue_work_on+0x106/0x1d0 kernel/workqueue.c:2501
gfs2_end_log_write+0xcd/0x6c0 fs/gfs2/lops.c:212
gfs2_log_submit_write+0x7e/0xb0 fs/gfs2/lops.c:245
gfs2_write_log_header+0x775/0x950 fs/gfs2/log.c:894
log_write_header+0x3d4/0x5f0 fs/gfs2/log.c:918
gfs2_log_shutdown+0xbb/0x2b0 fs/gfs2/log.c:1325
__gfs2_log_flush+0x16f9/0x1d90 fs/gfs2/log.c:1174
gfs2_log_flush+0x34/0x50 fs/gfs2/log.c:1216
gfs2_make_fs_ro+0x185/0x320 fs/gfs2/super.c:561
gfs2_put_super+0x235/0x870 fs/gfs2/super.c:603
generic_shutdown_super+0x13d/0x2d0 fs/super.c:751
kill_block_super+0x44/0xa0 fs/super.c:1903
deactivate_locked_super+0xbe/0x110 fs/super.c:586
cleanup_mnt+0x3d3/0x460 fs/namespace.c:1317
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:70 [inline]
exit_to_user_mode_loop+0x204/0x770 kernel/entry/common.c:101
__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:230 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline]
do_syscall_64+0x328/0x520 arch/x86/entry/syscall_64.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The buggy address belongs to the object at ffff888034454000
which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 840 bytes inside of
freed 8192-byte region [ffff888034454000, ffff888034456000)
The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x34450
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000040 ffff88801b042280 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 04fff00000000040 ffff88801b042280 dead000000000100 dead000000000122
head: 0000000000000000 0000000000020002 00000000f5000000 0000000000000000
head: 04fff00000000003 fffffffffffffe01 00000000ffffffff 00000000ffffffff
head: ffffffffffffffff 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 1, tgid 1 (swapper/0), ts 15762288625
set_page_owner include/linux/page_owner.h:33 [inline]
post_alloc_hook+0x1f9/0x250 mm/page_alloc.c:1871
prep_new_page mm/page_alloc.c:1879 [inline]
get_page_from_freelist+0x2209/0x2280 mm/page_alloc.c:3943
__alloc_frozen_pages_noprof+0x217/0x5a0 mm/page_alloc.c:5436
alloc_slab_page mm/slub.c:3347 [inline]
allocate_slab+0x7d/0x620 mm/slub.c:3462
new_slab mm/slub.c:3513 [inline]
refill_objects+0x2d5/0x350 mm/slub.c:7418
refill_sheaf mm/slub.c:2885 [inline]
__pcs_replace_empty_main+0x2c8/0x6c0 mm/slub.c:4774
alloc_from_pcs mm/slub.c:4850 [inline]
slab_alloc_node mm/slub.c:4984 [inline]
__do_kmalloc_node mm/slub.c:5413 [inline]
__kmalloc_noprof+0x47b/0x720 mm/slub.c:5439
_kmalloc_noprof include/linux/slab.h:995 [inline]
acpi_ut_initialize_buffer+0xca/0x170 drivers/acpi/acpica/utalloc.c:-1
acpi_rs_create_pci_routing_table+0x1c0/0xd90 drivers/acpi/acpica/rscreate.c:212
acpi_rs_get_prt_method_data+0xdf/0x150 drivers/acpi/acpica/rsutils.c:456
acpi_get_irq_routing_table+0x98/0xe0 drivers/acpi/acpica/rsxface.c:137
acpi_pci_irq_find_prt_entry+0x163/0x1040 drivers/acpi/pci_irq.c:215
acpi_pci_irq_lookup+0x45/0x690 drivers/acpi/pci_irq.c:299
acpi_pci_irq_enable+0x1ee/0x7a0 drivers/acpi/pci_irq.c:414
do_pci_enable_device+0x26f/0x4a0 drivers/pci/pci.c:2031
pci_enable_device_flags+0x5ab/0x700 drivers/pci/pci.c:2122
page last free pid 55 tgid 55 ts 15754532717 stack trace:
reset_page_owner include/linux/page_owner.h:26 [inline]
__free_pages_prepare mm/page_alloc.c:1418 [inline]
free_pages_prepare+0x9eb/0xaf0 mm/page_alloc.c:1463
__free_contig_range_common+0x174/0x340 mm/page_alloc.c:7072
__free_contig_range mm/page_alloc.c:7117 [inline]
free_pages_bulk+0x48/0x120 mm/page_alloc.c:5322
vm_area_free_pages mm/vmalloc.c:3461 [inline]
vfree+0x231/0x490 mm/vmalloc.c:3510
delayed_vfree_work+0x55/0x80 mm/vmalloc.c:3414
process_one_work kernel/workqueue.c:3396 [inline]
process_scheduled_works+0xc3d/0x1630 kernel/workqueue.c:3479
worker_thread+0xa47/0xfb0 kernel/workqueue.c:3560
kthread+0x38b/0x480 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
Memory state around the buggy address:
ffff888034454200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888034454280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888034454300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888034454380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888034454400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
---
This report is generated by a bot. It may contain errors.
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reply other threads:[~2026-10-09 0:58 UTC|newest]
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