syzbot


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

Status: upstream: reported syz repro on 2025/02/06 17:01
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+6663075ddb9be85fa6e5@syzkaller.appspotmail.com
First crash: 161d, last: 8h22m
Cause bisection: introduced by (bisect log) :
commit 14152654805256d760315ec24e414363bfa19a06
Author: Kent Overstreet <kent.overstreet@linux.dev>
Date: Mon Nov 25 05:21:27 2024 +0000

  bcachefs: Bad btree roots are now autofix

Crash: invalid opcode in corrupted (log)
Repro: syz .config
  
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [mm?] [bcachefs?] KASAN: slab-use-after-free Read in list_lru_del 0 (2) 2025/03/07 22:42
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream BUG: corrupted list in list_lru_del mm 8 2 944d 983d 0/29 auto-obsoleted due to no activity on 2023/03/15 19:34
Last patch testing requests (3)
Created Duration User Patch Repo Result
2025/03/16 02:44 1h11m retest repro upstream OK log
2025/03/16 02:44 19m retest repro upstream OK log
2025/03/15 18:54 21m retest repro upstream OK log

Sample crash report:
Zero length message leads to an empty skb
==================================================================
BUG: KASAN: slab-use-after-free in __list_del_entry_valid_or_report+0xb5/0x190 lib/list_debug.c:65
Read of size 8 at addr ffff888052cd0080 by task syz.0.0/5341

CPU: 0 UID: 0 PID: 5341 Comm: syz.0.0 Not tainted 6.16.0-rc6-syzkaller-00002-g155a3c003e55 #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0xca/0x230 mm/kasan/report.c:480
 kasan_report+0x118/0x150 mm/kasan/report.c:593
 __list_del_entry_valid_or_report+0xb5/0x190 lib/list_debug.c:65
 __list_del_entry_valid include/linux/list.h:124 [inline]
 __list_del_entry include/linux/list.h:215 [inline]
 list_del_init include/linux/list.h:287 [inline]
 list_lru_del+0x98/0x210 mm/list_lru.c:206
 gfs2_quota_cleanup+0x21e/0x6f0 fs/gfs2/quota.c:1532
 gfs2_make_fs_ro+0x27a/0x300 fs/gfs2/super.c:568
 gfs2_reconfigure+0x6a3/0xb20 fs/gfs2/ops_fstype.c:1595
 reconfigure_super+0x227/0x890 fs/super.c:1077
 do_remount fs/namespace.c:3386 [inline]
 path_mount+0xd18/0xfe0 fs/namespace.c:4218
 do_mount fs/namespace.c:4239 [inline]
 __do_sys_mount fs/namespace.c:4450 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4427
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f001b98e929
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:00007f0017df5038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f001bbb6080 RCX: 00007f001b98e929
RDX: 0000000000000000 RSI: 0000200000000000 RDI: 0000000000000000
RBP: 00007f001ba10ca1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000003376039 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f001bbb6080 R15: 00007ffeffe94bf8
 </TASK>

Allocated by task 5340:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:319 [inline]
 __kasan_slab_alloc+0x6c/0x80 mm/kasan/common.c:345
 kasan_slab_alloc include/linux/kasan.h:250 [inline]
 slab_post_alloc_hook mm/slub.c:4148 [inline]
 slab_alloc_node mm/slub.c:4197 [inline]
 kmem_cache_alloc_noprof+0x1c1/0x3c0 mm/slub.c:4204
 qd_alloc+0x50/0x250 fs/gfs2/quota.c:234
 gfs2_quota_init+0x777/0x1230 fs/gfs2/quota.c:1448
 gfs2_make_fs_rw+0x181/0x2b0 fs/gfs2/super.c:149
 gfs2_fill_super+0x1a91/0x20e0 fs/gfs2/ops_fstype.c:1278
 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1681
 gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1335
 vfs_get_tree+0x8f/0x2b0 fs/super.c:1804
 do_new_mount+0x24a/0xa40 fs/namespace.c:3902
 do_mount fs/namespace.c:4239 [inline]
 __do_sys_mount fs/namespace.c:4450 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4427
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 0:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3e/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x46/0x50 mm/kasan/generic.c:576
 poison_slab_object mm/kasan/common.c:247 [inline]
 __kasan_slab_free+0x62/0x70 mm/kasan/common.c:264
 kasan_slab_free include/linux/kasan.h:233 [inline]
 slab_free_hook mm/slub.c:2381 [inline]
 slab_free mm/slub.c:4643 [inline]
 kmem_cache_free+0x18f/0x400 mm/slub.c:4745
 gfs2_qd_dealloc+0x70/0xe0 fs/gfs2/quota.c:111
 rcu_do_batch kernel/rcu/tree.c:2576 [inline]
 rcu_core+0xca8/0x1710 kernel/rcu/tree.c:2832
 handle_softirqs+0x286/0x870 kernel/softirq.c:579
 __do_softirq kernel/softirq.c:613 [inline]
 invoke_softirq kernel/softirq.c:453 [inline]
 __irq_exit_rcu+0xca/0x1f0 kernel/softirq.c:680
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:696
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1050 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1050
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702

Last potentially related work creation:
 kasan_save_stack+0x3e/0x60 mm/kasan/common.c:47
 kasan_record_aux_stack+0xbd/0xd0 mm/kasan/generic.c:548
 __call_rcu_common kernel/rcu/tree.c:3094 [inline]
 call_rcu+0x157/0x9c0 kernel/rcu/tree.c:3214
 gfs2_quota_sync+0x3c4/0x460 fs/gfs2/quota.c:1361
 gfs2_sync_fs+0x4c/0xb0 fs/gfs2/super.c:660
 sync_filesystem+0xee/0x230 fs/sync.c:56
 gfs2_reconfigure+0xbb/0xb20 fs/gfs2/ops_fstype.c:1555
 reconfigure_super+0x227/0x890 fs/super.c:1077
 do_remount fs/namespace.c:3386 [inline]
 path_mount+0xd18/0xfe0 fs/namespace.c:4218
 do_mount fs/namespace.c:4239 [inline]
 __do_sys_mount fs/namespace.c:4450 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4427
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888052cd0000
 which belongs to the cache gfs2_quotad of size 272
The buggy address is located 128 bytes inside of
 freed 272-byte region [ffff888052cd0000, ffff888052cd0110)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x52cd0
flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000000 ffff888000684b40 dead000000000122 0000000000000000
raw: 0000000000000000 00000000800c000c 00000000f5000000 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 0x52c50(GFP_NOFS|__GFP_RECLAIMABLE|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5340, tgid 5339 (syz.0.0), ts 68650702778, free_ts 0
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
 prep_new_page mm/page_alloc.c:1712 [inline]
 get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3669
 __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959
 alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
 alloc_slab_page mm/slub.c:2451 [inline]
 allocate_slab+0x8a/0x3b0 mm/slub.c:2619
 new_slab mm/slub.c:2673 [inline]
 ___slab_alloc+0xbfc/0x1480 mm/slub.c:3859
 __slab_alloc mm/slub.c:3949 [inline]
 __slab_alloc_node mm/slub.c:4024 [inline]
 slab_alloc_node mm/slub.c:4185 [inline]
 kmem_cache_alloc_noprof+0x283/0x3c0 mm/slub.c:4204
 qd_alloc+0x50/0x250 fs/gfs2/quota.c:234
 gfs2_quota_init+0x777/0x1230 fs/gfs2/quota.c:1448
 gfs2_make_fs_rw+0x181/0x2b0 fs/gfs2/super.c:149
 gfs2_fill_super+0x1a91/0x20e0 fs/gfs2/ops_fstype.c:1278
 get_tree_bdev_flags+0x40e/0x4d0 fs/super.c:1681
 gfs2_get_tree+0x51/0x1e0 fs/gfs2/ops_fstype.c:1335
 vfs_get_tree+0x8f/0x2b0 fs/super.c:1804
 do_new_mount+0x24a/0xa40 fs/namespace.c:3902
 do_mount fs/namespace.c:4239 [inline]
 __do_sys_mount fs/namespace.c:4450 [inline]
 __se_sys_mount+0x317/0x410 fs/namespace.c:4427
page_owner free stack trace missing

Memory state around the buggy address:
 ffff888052ccff80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888052cd0000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888052cd0080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                   ^
 ffff888052cd0100: fb fb fc fc fc fc fc fc fc fc 00 00 00 00 00 00
 ffff888052cd0180: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Crashes (17):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/16 23:52 upstream 155a3c003e55 44f8051e .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in list_lru_del
2025/07/02 22:02 upstream b4911fb0b060 0cd59a8f .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in list_lru_del
2025/06/27 18:06 upstream 67a993863163 803ce19b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in list_lru_del
2025/06/25 16:05 upstream 7595b66ae9de 26d77996 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in list_lru_del
2025/05/31 06:36 upstream 8477ab143069 3d2f584d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in list_lru_del
2025/05/29 16:38 upstream 90b83efa6701 3d2f584d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in list_lru_del
2025/05/21 21:38 upstream 4a95bc121ccd f6063999 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in list_lru_del
2025/05/05 18:20 upstream 92a09c47464d 6ca47dd8 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in list_lru_del
2025/04/25 07:20 upstream e72e9e693307 e3715315 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in list_lru_del
2025/04/06 07:03 upstream 56f944529ec2 1c65791e .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in list_lru_del
2025/04/01 18:47 upstream 08733088b566 b8645499 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in list_lru_del
2025/03/21 21:27 upstream d07de43e3f05 c6512ef7 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in list_lru_del
2025/02/20 22:50 upstream e9a8cac0bf89 0808a665 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in list_lru_del
2025/02/06 06:31 upstream 92514ef226f5 577d049b .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in list_lru_del
2025/03/01 18:44 upstream 03d38806a902 c3901742 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs BUG: corrupted list in list_lru_del
2025/02/19 02:47 upstream 6537cfb395f3 9a14138f .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs BUG: corrupted list in list_lru_del
2025/02/06 13:59 upstream 92514ef226f5 1e1faf27 .config console log report syz / log [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro] ci-snapshot-upstream-root BUG: corrupted list in list_lru_del
* Struck through repros no longer work on HEAD.