KASAN: slab-use-after-free Read in lockref_get_not_dead (2)

Status: fixed on 2024/10/22 11:56
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+f82b36bffae7ef78b6a7@syzkaller.appspotmail.com
Fix commit: 4e32c25b58b9 libfs: fix get_stashed_dentry()
First crash: 699d, last: 699d
Cause bisection: failed (error log, bisect log)
  
▶ ▼ Discussions (2)
Title Replies (including bot) Last reply
[syzbot] [fs?] KASAN: slab-use-after-free Read in lockref_get_not_dead (2) 1 (3) 2024/09/06 22:45
[PATCH] libfs: fix get_stashed_dentry() 2 (2) 2024/09/06 18:09
▶ ▼ Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: slab-use-after-free Read in lockref_get_not_dead fs 19 1 870d 866d 0/29 auto-obsoleted due to no activity on 2024/06/13 05:36
▶ ▼ Last patch testing requests (1)
Created Duration User Patch Repo Result
2024/09/06 22:17 27m hdanton@sina.com patch net OK log

Sample crash report:
==================================================================
BUG: KASAN: slab-use-after-free in __lock_acquire+0x77/0x2040 kernel/locking/lockdep.c:5007
Read of size 8 at addr ffff88805c6ce248 by task syz.4.339/6895

CPU: 0 UID: 0 PID: 6895 Comm: syz.4.339 Not tainted 6.11.0-rc5-syzkaller-00154-g9b0874286768 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:93 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:119
 print_address_description mm/kasan/report.c:377 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:488
 kasan_report+0x143/0x180 mm/kasan/report.c:601
 __lock_acquire+0x77/0x2040 kernel/locking/lockdep.c:5007
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5759
 __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
 _raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
 spin_lock include/linux/spinlock.h:351 [inline]
 lockref_get_not_dead+0x26/0xc0 lib/lockref.c:184
 get_stashed_dentry fs/libfs.c:2128 [inline]
 path_from_stashed+0x218/0xb90 fs/libfs.c:2222
 proc_ns_get_link+0xf9/0x240 fs/proc/namespaces.c:61
 pick_link+0x631/0xd50
 step_into+0xca9/0x1080 fs/namei.c:1909
 open_last_lookups fs/namei.c:3674 [inline]
 path_openat+0x184b/0x3470 fs/namei.c:3883
 do_filp_open+0x235/0x490 fs/namei.c:3913
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1416
 do_sys_open fs/open.c:1431 [inline]
 __do_sys_openat fs/open.c:1447 [inline]
 __se_sys_openat fs/open.c:1442 [inline]
 __x64_sys_openat+0x247/0x2a0 fs/open.c:1442
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fab18f78850
Code: 48 89 44 24 20 75 93 44 89 54 24 0c e8 19 8f 02 00 44 8b 54 24 0c 89 da 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 38 44 89 c7 89 44 24 0c e8 6c 8f 02 00 8b 44
RSP: 002b:00007fab19c74f60 EFLAGS: 00000293 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fab18f78850
RDX: 0000000000000000 RSI: 00007fab18fe7a56 RDI: 00000000ffffff9c
RBP: 00007fab18fe7a56 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000001 R14: 00007fab19116130 R15: 00007ffe82b25778
 </TASK>

Allocated by task 6889:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 unpoison_slab_object mm/kasan/common.c:312 [inline]
 __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3988 [inline]
 slab_alloc_node mm/slub.c:4037 [inline]
 kmem_cache_alloc_lru_noprof+0x139/0x2b0 mm/slub.c:4056
 __d_alloc+0x31/0x700 fs/dcache.c:1631
 prepare_anon_dentry fs/libfs.c:2162 [inline]
 path_from_stashed+0x63a/0xb90 fs/libfs.c:2229
 proc_ns_get_link+0xf9/0x240 fs/proc/namespaces.c:61
 pick_link+0x631/0xd50
 step_into+0xca9/0x1080 fs/namei.c:1909
 open_last_lookups fs/namei.c:3674 [inline]
 path_openat+0x184b/0x3470 fs/namei.c:3883
 do_filp_open+0x235/0x490 fs/namei.c:3913
 do_sys_openat2+0x13e/0x1d0 fs/open.c:1416
 do_sys_open fs/open.c:1431 [inline]
 __do_sys_openat fs/open.c:1447 [inline]
 __se_sys_openat fs/open.c:1442 [inline]
 __x64_sys_openat+0x247/0x2a0 fs/open.c:1442
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 16:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
 kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
 poison_slab_object+0xe0/0x150 mm/kasan/common.c:240
 __kasan_slab_free+0x37/0x60 mm/kasan/common.c:256
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2252 [inline]
 slab_free mm/slub.c:4473 [inline]
 kmem_cache_free+0x145/0x350 mm/slub.c:4548
 rcu_do_batch kernel/rcu/tree.c:2569 [inline]
 rcu_core+0xafd/0x1830 kernel/rcu/tree.c:2843
 handle_softirqs+0x2c4/0x970 kernel/softirq.c:554
 run_ksoftirqd+0xca/0x130 kernel/softirq.c:928
 smpboot_thread_fn+0x544/0xa30 kernel/smpboot.c:164
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Last potentially related work creation:
 kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
 __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:541
 __call_rcu_common kernel/rcu/tree.c:3106 [inline]
 call_rcu+0x167/0xa70 kernel/rcu/tree.c:3210
 __dentry_kill+0x497/0x630 fs/dcache.c:629
 dput+0x19f/0x2b0 fs/dcache.c:852
 __fput+0x5f8/0x8a0 fs/file_table.c:430
 __do_sys_close fs/open.c:1566 [inline]
 __se_sys_close fs/open.c:1551 [inline]
 __x64_sys_close+0x7f/0x110 fs/open.c:1551
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88805c6ce178
 which belongs to the cache dentry of size 312
The buggy address is located 208 bytes inside of
 freed 312-byte region [ffff88805c6ce178, ffff88805c6ce2b0)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5c6ce
head: order:1 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff8880279abf01
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xfdffffff(slab)
raw: 00fff00000000040 ffff88801bafe8c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000150015 00000001fdffffff ffff8880279abf01
head: 00fff00000000040 ffff88801bafe8c0 dead000000000100 dead000000000122
head: 0000000000000000 0000000000150015 00000001fdffffff ffff8880279abf01
head: 00fff00000000001 ffffea000171b381 ffffffffffffffff 0000000000000000
head: 0000000000000002 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 1, migratetype Reclaimable, gfp_mask 0x1d20d0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_RECLAIMABLE), pid 5646, tgid 5645 (syz.1.52), ts 379968019454, free_ts 379948285619
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1493
 prep_new_page mm/page_alloc.c:1501 [inline]
 get_page_from_freelist+0x2e4c/0x2f10 mm/page_alloc.c:3439
 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4695
 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
 alloc_slab_page+0x5f/0x120 mm/slub.c:2321
 allocate_slab+0x5a/0x2f0 mm/slub.c:2484
 new_slab mm/slub.c:2537 [inline]
 ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3723
 __slab_alloc+0x58/0xa0 mm/slub.c:3813
 __slab_alloc_node mm/slub.c:3866 [inline]
 slab_alloc_node mm/slub.c:4025 [inline]
 kmem_cache_alloc_lru_noprof+0x1c5/0x2b0 mm/slub.c:4056
 __d_alloc+0x31/0x700 fs/dcache.c:1631
 d_alloc_pseudo+0x1f/0xb0 fs/dcache.c:1763
 alloc_path_pseudo fs/file_table.c:330 [inline]
 alloc_file_pseudo+0x123/0x290 fs/file_table.c:346
 sock_alloc_file+0xb8/0x290 net/socket.c:469
 sock_map_fd net/socket.c:494 [inline]
 __sys_socket+0x1dd/0x3c0 net/socket.c:1715
 __do_sys_socket net/socket.c:1720 [inline]
 __se_sys_socket net/socket.c:1718 [inline]
 __x64_sys_socket+0x7a/0x90 net/socket.c:1718
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
page last free pid 5643 tgid 5642 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1094 [inline]
 free_unref_page+0xd22/0xea0 mm/page_alloc.c:2612
 __slab_free+0x31b/0x3d0 mm/slub.c:4384
 qlink_free mm/kasan/quarantine.c:163 [inline]
 qlist_free_all+0x9e/0x140 mm/kasan/quarantine.c:179
 kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
 __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:322
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3988 [inline]
 slab_alloc_node mm/slub.c:4037 [inline]
 kmem_cache_alloc_noprof+0x135/0x2a0 mm/slub.c:4044
 create_nsproxy kernel/nsproxy.c:56 [inline]
 create_new_namespaces+0x34/0x7b0 kernel/nsproxy.c:74
 prepare_nsset kernel/nsproxy.c:335 [inline]
 __do_sys_setns kernel/nsproxy.c:569 [inline]
 __se_sys_setns+0x2cb/0x1c10 kernel/nsproxy.c:546
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
 ffff88805c6ce100: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc fa
 ffff88805c6ce180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88805c6ce200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                              ^
 ffff88805c6ce280: fb fb fb fb fb fb fc fc fc fc fc fc fc fc fa fb
 ffff88805c6ce300: 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
2024/09/02 08:37 net 9b0874286768 1eda0d14 .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce KASAN: slab-use-after-free Read in lockref_get_not_dead
* Struck through repros no longer work on HEAD.