Hello,
syzbot found the following issue on:
HEAD commit: d96eb99e2f0e Linux 6.6.99
git tree: linux-6.6.y
console output:
https://syzkaller.appspot.com/x/log.txt?x=13a68f22580000
kernel config:
https://syzkaller.appspot.com/x/.config?x=bfd82343ac39d3b
dashboard link:
https://syzkaller.appspot.com/bug?extid=f9e4c812b9ab2e943d86
compiler: Debian clang version 20.1.7 (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD 20.1.7
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image:
https://storage.googleapis.com/syzbot-assets/11b332f11d00/disk-d96eb99e.raw.xz
vmlinux:
https://storage.googleapis.com/syzbot-assets/8a063193b98f/vmlinux-d96eb99e.xz
kernel image:
https://storage.googleapis.com/syzbot-assets/b36214b822e5/bzImage-d96eb99e.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by:
syzbot+f9e4c8...@syzkaller.appspotmail.com
gfs2: fsid=norecovery.s: Error checking journal for spectator mount.
==================================================================
BUG: KASAN: slab-use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: slab-use-after-free in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
BUG: KASAN: slab-use-after-free in mapping_unevictable include/linux/pagemap.h:256 [inline]
BUG: KASAN: slab-use-after-free in folio_evictable mm/internal.h:207 [inline]
BUG: KASAN: slab-use-after-free in lru_add_fn+0x279/0x1720 mm/swap.c:173
Read of size 8 at addr ffff88805b86c3c8 by task syz.1.695/7406
CPU: 0 PID: 7406 Comm: syz.1.695 Not tainted 6.6.99-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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/0x200 mm/kasan/report.c:466
kasan_report+0x117/0x150 mm/kasan/report.c:579
check_region_inline mm/kasan/generic.c:-1 [inline]
kasan_check_range+0x288/0x290 mm/kasan/generic.c:187
instrument_atomic_read include/linux/instrumented.h:68 [inline]
_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
mapping_unevictable include/linux/pagemap.h:256 [inline]
folio_evictable mm/internal.h:207 [inline]
lru_add_fn+0x279/0x1720 mm/swap.c:173
folio_batch_move_lru+0x2e7/0x6b0 mm/swap.c:209
lru_add_drain_cpu+0x10e/0x8c0 mm/swap.c:644
lru_add_drain+0x121/0x3e0 mm/swap.c:744
__folio_batch_release+0x48/0xe0 mm/swap.c:1039
folio_batch_release include/linux/pagevec.h:83 [inline]
shmem_undo_range+0x5d0/0x1a40 mm/shmem.c:1027
shmem_truncate_range mm/shmem.c:1136 [inline]
shmem_evict_inode+0x273/0xa70 mm/shmem.c:1265
evict+0x486/0x870 fs/inode.c:705
__dentry_kill+0x431/0x650 fs/dcache.c:611
dentry_kill+0xb8/0x290 fs/dcache.c:-1
dput+0xfe/0x1e0 fs/dcache.c:918
__fput+0x5e5/0x970 fs/file_table.c:392
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+0xb1/0x140 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
RIP: 0033:0x7fba8058e5ab
Code: 00 48 89 44 24 18 31 c0 48 8d 44 24 60 c7 04 24 10 00 00 00 48 89 44 24 08 48 8d 44 24 20 48 89 44 24 10 b8 10 00 00 00 0f 05 <89> c2 3d 00 f0 ff ff 77 1c 48 8b 44 24 18 64 48 2b 04 25 28 00 00
RSP: 002b:00007fba814abe10 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: 0000000000000000 RBX: ffffffffffffffff RCX: 00007fba8058e5ab
RDX: 0000000000000000 RSI: 0000000000004c01 RDI: 0000000000000003
RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000200001
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000005
R13: 00007fba814abeb0 R14: 00000000000125bb R15: 0000200000000180
</TASK>
Allocated by task 7406:
kasan_save_stack mm/kasan/common.c:45 [inline]
kasan_set_track+0x4e/0x70 mm/kasan/common.c:52
__kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:328
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:3485 [inline]
slab_alloc mm/slub.c:3493 [inline]
__kmem_cache_alloc_lru mm/slub.c:3500 [inline]
kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3509
gfs2_glock_get+0x288/0xed0 fs/gfs2/glock.c:1212
gfs2_inode_lookup+0x219/0xae0 fs/gfs2/inode.c:135
gfs2_dir_search+0x169/0x220 fs/gfs2/dir.c:1664
gfs2_lookupi+0x3d9/0x5a0 fs/gfs2/inode.c:339
gfs2_jindex_hold fs/gfs2/ops_fstype.c:609 [inline]
init_journal+0x54b/0x2260 fs/gfs2/ops_fstype.c:751
init_inodes+0xdb/0x320 fs/gfs2/ops_fstype.c:886
gfs2_fill_super+0x1815/0x1f80 fs/gfs2/ops_fstype.c:1266
get_tree_bdev+0x3e4/0x510 fs/super.c:1591
gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1344
vfs_get_tree+0x8c/0x280 fs/super.c:1764
do_new_mount+0x24b/0xa40 fs/namespace.c:3366
do_mount fs/namespace.c:3706 [inline]
__do_sys_mount fs/namespace.c:3915 [inline]
__se_sys_mount+0x2da/0x3c0 fs/namespace.c:3892
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 22:
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:1806 [inline]
slab_free_freelist_hook+0x130/0x1b0 mm/slub.c:1832
slab_free mm/slub.c:3816 [inline]
kmem_cache_free+0xf8/0x280 mm/slub.c:3838
rcu_do_batch kernel/rcu/tree.c:2194 [inline]
rcu_core+0xcc4/0x1720 kernel/rcu/tree.c:2467
handle_softirqs+0x280/0x820 kernel/softirq.c:578
run_ksoftirqd+0x9c/0xf0 kernel/softirq.c:950
smpboot_thread_fn+0x635/0xa00 kernel/smpboot.c:164
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
Last potentially related work creation:
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:45
__kasan_record_aux_stack+0xaf/0xc0 mm/kasan/generic.c:492
__call_rcu_common kernel/rcu/tree.c:2721 [inline]
call_rcu+0x158/0x930 kernel/rcu/tree.c:2837
__gfs2_glock_free+0xb3a/0xc80 fs/gfs2/glock.c:174
gfs2_glock_free+0x3c/0xa0 fs/gfs2/glock.c:180
gfs2_glock_put_eventually fs/gfs2/super.c:1275 [inline]
gfs2_evict_inode+0x65a/0x1220 fs/gfs2/super.c:1557
evict+0x486/0x870 fs/inode.c:705
gfs2_jindex_free+0x39d/0x440 fs/gfs2/super.c:79
init_journal+0x8f2/0x2260 fs/gfs2/ops_fstype.c:868
init_inodes+0xdb/0x320 fs/gfs2/ops_fstype.c:886
gfs2_fill_super+0x1815/0x1f80 fs/gfs2/ops_fstype.c:1266
get_tree_bdev+0x3e4/0x510 fs/super.c:1591
gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1344
vfs_get_tree+0x8c/0x280 fs/super.c:1764
do_new_mount+0x24b/0xa40 fs/namespace.c:3366
do_mount fs/namespace.c:3706 [inline]
__do_sys_mount fs/namespace.c:3915 [inline]
__se_sys_mount+0x2da/0x3c0 fs/namespace.c:3892
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
Second to last potentially related work creation:
kasan_save_stack+0x3e/0x60 mm/kasan/common.c:45
__kasan_record_aux_stack+0xaf/0xc0 mm/kasan/generic.c:492
insert_work+0x3d/0x310 kernel/workqueue.c:1651
__queue_work+0xc39/0x1020 kernel/workqueue.c:1800
queue_delayed_work_on+0x12a/0x1e0 kernel/workqueue.c:1987
queue_delayed_work include/linux/workqueue.h:577 [inline]
gfs2_glock_queue_work fs/gfs2/glock.c:278 [inline]
do_xmote+0xcf5/0x12c0 fs/gfs2/glock.c:842
glock_work_func+0x29e/0x4c0 fs/gfs2/glock.c:1121
process_one_work kernel/workqueue.c:2634 [inline]
process_scheduled_works+0xa45/0x15b0 kernel/workqueue.c:2711
worker_thread+0xa55/0xfc0 kernel/workqueue.c:2792
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
The buggy address belongs to the object at ffff88805b86c000
which belongs to the cache gfs2_glock(aspace) of size 1224
The buggy address is located 968 bytes inside of
freed 1224-byte region [ffff88805b86c000, ffff88805b86c4c8)
The buggy address belongs to the physical page:
page:ffffea00016e1b00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5b86c
head:ffffea00016e1b00 order:2 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888143a9a000 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800c000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 2, migratetype Unmovable, gfp_mask 0x1d2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 6438, tgid 6437 (syz.2.264), ts 94738629084, free_ts 94198413754
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:1876
allocate_slab mm/slub.c:2023 [inline]
new_slab+0x87/0x2e0 mm/slub.c:2076
___slab_alloc+0xc6d/0x12f0 mm/slub.c:3230
__slab_alloc mm/slub.c:3329 [inline]
__slab_alloc_node mm/slub.c:3382 [inline]
slab_alloc_node mm/slub.c:3475 [inline]
slab_alloc mm/slub.c:3493 [inline]
__kmem_cache_alloc_lru mm/slub.c:3500 [inline]
kmem_cache_alloc+0x1b7/0x2e0 mm/slub.c:3509
gfs2_glock_get+0x288/0xed0 fs/gfs2/glock.c:1212
gfs2_inode_lookup+0x219/0xae0 fs/gfs2/inode.c:135
gfs2_lookup_root fs/gfs2/ops_fstype.c:462 [inline]
init_sb+0xa2c/0x1310 fs/gfs2/ops_fstype.c:529
gfs2_fill_super+0x14c2/0x1f80 fs/gfs2/ops_fstype.c:1233
get_tree_bdev+0x3e4/0x510 fs/super.c:1591
gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1344
vfs_get_tree+0x8c/0x280 fs/super.c:1764
do_new_mount+0x24b/0xa40 fs/namespace.c:3366
do_mount fs/namespace.c:3706 [inline]
__do_sys_mount fs/namespace.c:3915 [inline]
__se_sys_mount+0x2da/0x3c0 fs/namespace.c:3892
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
discard_slab mm/slub.c:2122 [inline]
__unfreeze_partials+0x1cf/0x210 mm/slub.c:2662
put_cpu_partial+0x17c/0x250 mm/slub.c:2738
__slab_free+0x31d/0x410 mm/slub.c:3686
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:3485 [inline]
slab_alloc mm/slub.c:3493 [inline]
__kmem_cache_alloc_lru mm/slub.c:3500 [inline]
kmem_cache_alloc+0x11e/0x2e0 mm/slub.c:3509
vm_area_dup+0x27/0x270 kernel/fork.c:501
__split_vma+0x19f/0xc00 mm/mmap.c:2369
do_vmi_align_munmap+0x2dc/0x1660 mm/mmap.c:2497
do_vmi_munmap+0x252/0x2d0 mm/mmap.c:2656
__vm_munmap+0x193/0x3c0 mm/mmap.c:2957
__do_sys_munmap mm/mmap.c:2974 [inline]
__se_sys_munmap mm/mmap.c:2971 [inline]
__x64_sys_munmap+0x60/0x70 mm/mmap.c:2971
Memory state around the buggy address:
ffff88805b86c280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88805b86c300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88805b86c380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88805b86c400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88805b86c480: fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc
==================================================================
---
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