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KASAN: use-after-free Read in gfs2_quota_unhold (2)

Status: upstream: reported on 2025/08/18 13:34
Reported-by: syzbot+3d023e11befb4a5972ab@syzkaller.appspotmail.com
First crash: 10d, last: 10d
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 KASAN: use-after-free Read in gfs2_quota_unhold 19 3 249d 249d 0/3 auto-obsoleted due to no activity on 2025/04/01 15:15

Sample crash report:
RBP: 00007fed7661ce19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fed767c1128 R14: 00007fed767c1090 R15: 00007ffc8904a588
 </TASK>
==================================================================
BUG: KASAN: use-after-free in bh_put fs/gfs2/quota.c:414 [inline]
BUG: KASAN: use-after-free in qdsb_put fs/gfs2/quota.c:533 [inline]
BUG: KASAN: use-after-free in gfs2_quota_unhold+0x17a/0x5d0 fs/gfs2/quota.c:652
Read of size 8 at addr ffff8880603470c8 by task syz.2.6/4354

CPU: 1 PID: 4354 Comm: syz.2.6 Not tainted 5.15.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
 <TASK>
 dump_stack_lvl+0x168/0x230 lib/dump_stack.c:106
 print_address_description+0x60/0x2d0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0xdf/0x130 mm/kasan/report.c:451
 bh_put fs/gfs2/quota.c:414 [inline]
 qdsb_put fs/gfs2/quota.c:533 [inline]
 gfs2_quota_unhold+0x17a/0x5d0 fs/gfs2/quota.c:652
 gfs2_quota_lock+0x1c7/0x7d0 fs/gfs2/quota.c:1095
 gfs2_quota_lock_check fs/gfs2/quota.h:50 [inline]
 do_grow fs/gfs2/bmap.c:2065 [inline]
 gfs2_setattr_size+0x357/0x810 fs/gfs2/bmap.c:2140
 gfs2_setattr+0x252/0x400 fs/gfs2/inode.c:2006
 notify_change+0xbcd/0xee0 fs/attr.c:505
 do_truncate+0x197/0x220 fs/open.c:65
 do_sys_ftruncate+0x31b/0x3d0 fs/open.c:193
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fed76599be9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fed747e0038 EFLAGS: 00000246 ORIG_RAX: 000000000000004d
RAX: ffffffffffffffda RBX: 00007fed767c1090 RCX: 00007fed76599be9
RDX: 0000000000000000 RSI: 000000000000c17a RDI: 0000000000000006
RBP: 00007fed7661ce19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fed767c1128 R14: 00007fed767c1090 R15: 00007ffc8904a588
 </TASK>

Allocated by task 4354:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 __kasan_slab_alloc+0x9c/0xd0 mm/kasan/common.c:467
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook+0x4c/0x380 mm/slab.h:519
 slab_alloc_node mm/slub.c:3220 [inline]
 slab_alloc mm/slub.c:3228 [inline]
 kmem_cache_alloc+0x100/0x290 mm/slub.c:3233
 kmem_cache_zalloc include/linux/slab.h:725 [inline]
 qd_alloc+0x50/0x260 fs/gfs2/quota.c:216
 qd_get+0x24f/0x5f0 fs/gfs2/quota.c:275
 qdsb_get+0x2a/0x3c0 fs/gfs2/quota.c:510
 gfs2_quota_hold+0x194/0x5d0 fs/gfs2/quota.c:604
 gfs2_quota_lock+0xa0/0x7d0 fs/gfs2/quota.c:1076
 gfs2_quota_lock_check fs/gfs2/quota.h:50 [inline]
 do_grow fs/gfs2/bmap.c:2065 [inline]
 gfs2_setattr_size+0x357/0x810 fs/gfs2/bmap.c:2140
 gfs2_setattr+0x252/0x400 fs/gfs2/inode.c:2006
 notify_change+0xbcd/0xee0 fs/attr.c:505
 do_truncate+0x197/0x220 fs/open.c:65
 do_sys_ftruncate+0x31b/0x3d0 fs/open.c:193
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Freed by task 14:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x70 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd5/0x110 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1705 [inline]
 slab_free_freelist_hook+0xea/0x170 mm/slub.c:1731
 slab_free mm/slub.c:3499 [inline]
 kmem_cache_free+0x8f/0x210 mm/slub.c:3515
 rcu_do_batch kernel/rcu/tree.c:2523 [inline]
 rcu_core+0x962/0x15d0 kernel/rcu/tree.c:2763
 handle_softirqs+0x328/0x820 kernel/softirq.c:576
 run_ksoftirqd+0x98/0xf0 kernel/softirq.c:943
 smpboot_thread_fn+0x4f6/0x970 kernel/smpboot.c:164
 kthread+0x436/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Last potentially related work creation:
 kasan_save_stack+0x35/0x60 mm/kasan/common.c:38
 kasan_record_aux_stack+0xb8/0x100 mm/kasan/generic.c:348
 __call_rcu kernel/rcu/tree.c:3011 [inline]
 call_rcu+0x182/0x930 kernel/rcu/tree.c:3091
 gfs2_quota_cleanup+0x43c/0x6a0 fs/gfs2/quota.c:1490
 gfs2_make_fs_ro+0x491/0x5d0 fs/gfs2/super.c:557
 signal_our_withdraw fs/gfs2/util.c:166 [inline]
 gfs2_withdraw+0x5f9/0x1460 fs/gfs2/util.c:343
 gfs2_meta_check_ii+0x6e/0x80 fs/gfs2/util.c:498
 gfs2_metatype_check_i fs/gfs2/util.h:126 [inline]
 gfs2_meta_buffer+0x232/0x310 fs/gfs2/meta_io.c:493
 gfs2_meta_inode_buffer fs/gfs2/meta_io.h:70 [inline]
 gfs2_inode_refresh+0xb5/0xfe0 fs/gfs2/glops.c:481
 inode_go_lock+0x127/0x470 fs/gfs2/glops.c:510
 do_promote+0x741/0xab0 fs/gfs2/glock.c:507
 finish_xmote+0x514/0xb70 fs/gfs2/glock.c:678
 do_xmote+0x7b6/0x1120 fs/gfs2/glock.c:824
 gfs2_glock_nq+0xc7a/0x1550 fs/gfs2/glock.c:1534
 gfs2_glock_nq_init fs/gfs2/glock.h:246 [inline]
 do_glock+0x3ae/0x6e0 fs/gfs2/quota.c:1043
 gfs2_quota_lock+0x1ab/0x7d0 fs/gfs2/quota.c:1085
 gfs2_quota_lock_check fs/gfs2/quota.h:50 [inline]
 do_grow fs/gfs2/bmap.c:2065 [inline]
 gfs2_setattr_size+0x357/0x810 fs/gfs2/bmap.c:2140
 gfs2_setattr+0x252/0x400 fs/gfs2/inode.c:2006
 notify_change+0xbcd/0xee0 fs/attr.c:505
 do_truncate+0x197/0x220 fs/open.c:65
 do_sys_ftruncate+0x31b/0x3d0 fs/open.c:193
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff888060347000
 which belongs to the cache gfs2_quotad of size 272
The buggy address is located 200 bytes inside of
 272-byte region [ffff888060347000, ffff888060347110)
The buggy address belongs to the page:
page:ffffea000180d1c0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x60347
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 0000000000000000 dead000000000122 ffff888146ad4780
raw: 0000000000000000 00000000800c000c 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Reclaimable, gfp_mask 0x112c50(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_HARDWALL|__GFP_RECLAIMABLE), pid 4354, ts 63236995435, free_ts 12503716113
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x1b77/0x1c60 mm/page_alloc.c:4192
 __alloc_pages+0x1e1/0x470 mm/page_alloc.c:5474
 alloc_slab_page mm/slub.c:1775 [inline]
 allocate_slab mm/slub.c:1912 [inline]
 new_slab+0xc0/0x4b0 mm/slub.c:1975
 ___slab_alloc+0x81e/0xdf0 mm/slub.c:3008
 __slab_alloc mm/slub.c:3095 [inline]
 slab_alloc_node mm/slub.c:3186 [inline]
 slab_alloc mm/slub.c:3228 [inline]
 kmem_cache_alloc+0x195/0x290 mm/slub.c:3233
 kmem_cache_zalloc include/linux/slab.h:725 [inline]
 qd_alloc+0x50/0x260 fs/gfs2/quota.c:216
 qd_get+0x24f/0x5f0 fs/gfs2/quota.c:275
 qdsb_get+0x2a/0x3c0 fs/gfs2/quota.c:510
 gfs2_quota_hold+0x194/0x5d0 fs/gfs2/quota.c:604
 gfs2_quota_lock+0xa0/0x7d0 fs/gfs2/quota.c:1076
 gfs2_quota_lock_check fs/gfs2/quota.h:50 [inline]
 do_grow fs/gfs2/bmap.c:2065 [inline]
 gfs2_setattr_size+0x357/0x810 fs/gfs2/bmap.c:2140
 gfs2_setattr+0x252/0x400 fs/gfs2/inode.c:2006
 notify_change+0xbcd/0xee0 fs/attr.c:505
 do_truncate+0x197/0x220 fs/open.c:65
 do_sys_ftruncate+0x31b/0x3d0 fs/open.c:193
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:80
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0x637/0x6c0 mm/page_alloc.c:3317
 free_unref_page+0x94/0x280 mm/page_alloc.c:3396
 free_contig_range+0x96/0xf0 mm/page_alloc.c:9393
 destroy_args+0xef/0x8b0 mm/debug_vm_pgtable.c:1018
 debug_vm_pgtable+0x318/0x370 mm/debug_vm_pgtable.c:1331
 do_one_initcall+0x1ee/0x680 init/main.c:1302
 do_initcall_level+0x137/0x1f0 init/main.c:1375
 do_initcalls+0x4b/0x90 init/main.c:1391
 kernel_init_freeable+0x3ce/0x560 init/main.c:1615
 kernel_init+0x19/0x1b0 init/main.c:1506
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Memory state around the buggy address:
 ffff888060346f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888060347000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888060347080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff888060347100: fb fb fc fc fc fc fc fc fc fc fa fb fb fb fb fb
 ffff888060347180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/08/18 13:33 linux-5.15.y c79648372d02 1804e95e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in gfs2_quota_unhold
* Struck through repros no longer work on HEAD.