syzbot


possible deadlock in stack_depot_save_flags

Status: upstream: reported on 2024/04/25 18:26
Subsystems: bpf
[Documentation on labels]
Reported-by: syzbot+c065d8dfbb5ad8cbdceb@syzkaller.appspotmail.com
First crash: 61d, last: 16d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bpf?] possible deadlock in stack_depot_save_flags 0 (1) 2024/04/25 18:26

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.10.0-rc2-syzkaller-00022-g32f88d65f01b #0 Not tainted
------------------------------------------------------
syz-executor.2/6675 is trying to acquire lock:
ffffffff8ea565e8 (pool_lock#2){-.-.}-{2:2}, at: stack_depot_save_flags+0x240/0x830 lib/stackdepot.c:633

but task is already holding lock:
ffff88807a7c21f8 (&trie->lock){-.-.}-{2:2}, at: trie_update_elem+0xc8/0xc00 kernel/bpf/lpm_trie.c:333

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&trie->lock){-.-.}-{2:2}:
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
       trie_delete_elem+0x96/0x6a0 kernel/bpf/lpm_trie.c:462
       0xffffffffa00008a2
       bpf_dispatcher_nop_func include/linux/bpf.h:1243 [inline]
       __bpf_prog_run include/linux/filter.h:691 [inline]
       bpf_prog_run include/linux/filter.h:698 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2403 [inline]
       bpf_trace_run2+0x2ee/0x540 kernel/trace/bpf_trace.c:2444
       trace_contention_end+0x114/0x140 include/trace/events/lock.h:122
       __pv_queued_spin_lock_slowpath+0xb81/0xdc0 kernel/locking/qspinlock.c:557
       pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt.h:584 [inline]
       queued_spin_lock_slowpath+0x42/0x50 arch/x86/include/asm/qspinlock.h:51
       queued_spin_lock include/asm-generic/qspinlock.h:114 [inline]
       do_raw_spin_lock+0x272/0x370 kernel/locking/spinlock_debug.c:116
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:111 [inline]
       _raw_spin_lock_irqsave+0xe1/0x120 kernel/locking/spinlock.c:162
       stack_depot_save_flags+0x240/0x830 lib/stackdepot.c:633
       kasan_save_stack mm/kasan/common.c:48 [inline]
       kasan_save_track+0x51/0x80 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:3940 [inline]
       slab_alloc_node mm/slub.c:4000 [inline]
       kmem_cache_alloc_noprof+0x135/0x2a0 mm/slub.c:4007
       fill_pool lib/debugobjects.c:168 [inline]
       debug_objects_fill_pool+0x3ea/0x9b0 lib/debugobjects.c:615
       debug_object_activate+0x135/0x510 lib/debugobjects.c:704
       debug_rcu_head_queue kernel/rcu/rcu.h:227 [inline]
       __call_rcu_common kernel/rcu/tree.c:3057 [inline]
       call_rcu+0x97/0xa70 kernel/rcu/tree.c:3176
       xa_node_free lib/xarray.c:259 [inline]
       xas_delete_node lib/xarray.c:496 [inline]
       update_node lib/xarray.c:760 [inline]
       xas_store+0xd2c/0x1890 lib/xarray.c:845
       page_cache_delete mm/filemap.c:149 [inline]
       __filemap_remove_folio+0x585/0x9e0 mm/filemap.c:232
       filemap_remove_folio+0x109/0x2e0 mm/filemap.c:264
       truncate_inode_folio+0x5d/0x70 mm/truncate.c:195
       shmem_undo_range+0x45d/0x1df0 mm/shmem.c:1001
       shmem_truncate_range mm/shmem.c:1114 [inline]
       shmem_evict_inode+0x29b/0xa60 mm/shmem.c:1242
       evict+0x2aa/0x630 fs/inode.c:667
       __dentry_kill+0x20d/0x630 fs/dcache.c:603
       dput+0x19f/0x2b0 fs/dcache.c:845
       __fput+0x68c/0x8b0 fs/file_table.c:430
       __do_sys_close fs/open.c:1555 [inline]
       __se_sys_close fs/open.c:1540 [inline]
       __x64_sys_close+0x7f/0x110 fs/open.c:1540
       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

-> #0 (pool_lock#2){-.-.}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3134 [inline]
       check_prevs_add kernel/locking/lockdep.c:3253 [inline]
       validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3869
       __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
       stack_depot_save_flags+0x240/0x830 lib/stackdepot.c:633
       save_stack+0x109/0x1f0 mm/page_owner.c:157
       __set_page_owner+0x92/0x800 mm/page_owner.c:320
       set_page_owner include/linux/page_owner.h:32 [inline]
       post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1468
       prep_new_page mm/page_alloc.c:1476 [inline]
       get_page_from_freelist+0x2e2d/0x2ee0 mm/page_alloc.c:3402
       __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4660
       __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
       alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
       __kmalloc_large_node+0x8b/0x1d0 mm/slub.c:4066
       __do_kmalloc_node mm/slub.c:4109 [inline]
       __kmalloc_node_noprof+0x2d2/0x440 mm/slub.c:4128
       kmalloc_node_noprof include/linux/slab.h:681 [inline]
       bpf_map_kmalloc_node+0xd3/0x1c0 kernel/bpf/syscall.c:422
       lpm_trie_node_alloc kernel/bpf/lpm_trie.c:299 [inline]
       trie_update_elem+0x1cd/0xc00 kernel/bpf/lpm_trie.c:342
       bpf_map_update_value+0x4d5/0x540 kernel/bpf/syscall.c:203
       map_update_elem+0x53a/0x6f0 kernel/bpf/syscall.c:1654
       __sys_bpf+0x76f/0x810 kernel/bpf/syscall.c:5675
       __do_sys_bpf kernel/bpf/syscall.c:5794 [inline]
       __se_sys_bpf kernel/bpf/syscall.c:5792 [inline]
       __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5792
       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

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&trie->lock);
                               lock(pool_lock#2);
                               lock(&trie->lock);
  lock(pool_lock#2);

 *** DEADLOCK ***

2 locks held by syz-executor.2/6675:
 #0: ffffffff8e333f60 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #0: ffffffff8e333f60 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #0: ffffffff8e333f60 (rcu_read_lock){....}-{1:2}, at: bpf_map_update_value+0x3c4/0x540 kernel/bpf/syscall.c:202
 #1: ffff88807a7c21f8 (&trie->lock){-.-.}-{2:2}, at: trie_update_elem+0xc8/0xc00 kernel/bpf/lpm_trie.c:333

stack backtrace:
CPU: 0 PID: 6675 Comm: syz-executor.2 Not tainted 6.10.0-rc2-syzkaller-00022-g32f88d65f01b #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2187
 check_prev_add kernel/locking/lockdep.c:3134 [inline]
 check_prevs_add kernel/locking/lockdep.c:3253 [inline]
 validate_chain+0x18e0/0x5900 kernel/locking/lockdep.c:3869
 __lock_acquire+0x1346/0x1fd0 kernel/locking/lockdep.c:5137
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
 stack_depot_save_flags+0x240/0x830 lib/stackdepot.c:633
 save_stack+0x109/0x1f0 mm/page_owner.c:157
 __set_page_owner+0x92/0x800 mm/page_owner.c:320
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1468
 prep_new_page mm/page_alloc.c:1476 [inline]
 get_page_from_freelist+0x2e2d/0x2ee0 mm/page_alloc.c:3402
 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4660
 __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
 alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
 __kmalloc_large_node+0x8b/0x1d0 mm/slub.c:4066
 __do_kmalloc_node mm/slub.c:4109 [inline]
 __kmalloc_node_noprof+0x2d2/0x440 mm/slub.c:4128
 kmalloc_node_noprof include/linux/slab.h:681 [inline]
 bpf_map_kmalloc_node+0xd3/0x1c0 kernel/bpf/syscall.c:422
 lpm_trie_node_alloc kernel/bpf/lpm_trie.c:299 [inline]
 trie_update_elem+0x1cd/0xc00 kernel/bpf/lpm_trie.c:342
 bpf_map_update_value+0x4d5/0x540 kernel/bpf/syscall.c:203
 map_update_elem+0x53a/0x6f0 kernel/bpf/syscall.c:1654
 __sys_bpf+0x76f/0x810 kernel/bpf/syscall.c:5675
 __do_sys_bpf kernel/bpf/syscall.c:5794 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5792 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5792
 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: 0033:0x7f2096a7cee9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f20977ea0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007f2096bb3f80 RCX: 00007f2096a7cee9
RDX: 0000000000000020 RSI: 0000000020000000 RDI: 0000000000000002
RBP: 00007f2096ada6fe R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f2096bb3f80 R15: 00007fff84379b78
 </TASK>

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/05 10:04 upstream 32f88d65f01b e1e2c66e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in stack_depot_save_flags
2024/05/03 05:01 upstream 49a73b1652c5 ddfc15a1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in stack_depot_save_flags
2024/04/21 18:19 upstream 977b1ef51866 af24b050 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-root possible deadlock in stack_depot_save_flags
2024/04/25 01:50 bpf 443574b03387 8bdc0f22 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-bpf-kasan-gce possible deadlock in stack_depot_save_flags
* Struck through repros no longer work on HEAD.