Message-ID: <0000000000001ae1d40616efed8e@google.com>
Date: Thu, 25 Apr 2024 11:26:31 -0700
From: syzbot <syzbot+c065d8dfbb5ad8cbdceb@...kaller.appspotmail.com>
To: andrii@...nel.org, ast@...nel.org, bpf@...r.kernel.org, 
	daniel@...earbox.net, eddyz87@...il.com, haoluo@...gle.com, 
	john.fastabend@...il.com, jolsa@...nel.org, kpsingh@...nel.org, 
	linux-kernel@...r.kernel.org, martin.lau@...ux.dev, sdf@...gle.com, 
	song@...nel.org, syzkaller-bugs@...glegroups.com, yonghong.song@...ux.dev
Subject: [syzbot] [bpf?] possible deadlock in stack_depot_save_flags

Hello,

syzbot found the following issue on:

HEAD commit:    977b1ef51866 Merge tag 'block-6.9-20240420' of git://git.k..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=11e9daf5180000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d239903bd07761e5
dashboard link: https://syzkaller.appspot.com/bug?extid=c065d8dfbb5ad8cbdceb
compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/08d7b6e107aa/disk-977b1ef5.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/9c5e543ffdcf/vmlinux-977b1ef5.xz
kernel image: https://storage.googleapis.com/syzbot-assets/04a6d79d2f69/bzImage-977b1ef5.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c065d8dfbb5ad8cbdceb@...kaller.appspotmail.com

======================================================
WARNING: possible circular locking dependency detected
6.9.0-rc4-syzkaller-00266-g977b1ef51866 #0 Not tainted
------------------------------------------------------
syz-executor.3/5489 is trying to acquire lock:
ffffffff8ea48ea8 (pool_lock#2){-.-.}-{2:2}, at: stack_depot_save_flags+0x240/0x830 lib/stackdepot.c:640

but task is already holding lock:
ffff8880121cf9f8 (&trie->lock){-.-.}-{2:2}, at: trie_update_elem+0xcb/0xc10 kernel/bpf/lpm_trie.c:324

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:451
       0xffffffffa0000856
       bpf_dispatcher_nop_func include/linux/bpf.h:1234 [inline]
       __bpf_prog_run include/linux/filter.h:657 [inline]
       bpf_prog_run include/linux/filter.h:664 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2381 [inline]
       bpf_trace_run2+0x206/0x420 kernel/trace/bpf_trace.c:2420
       trace_contention_end+0x114/0x140 include/trace/events/lock.h:122
       __pv_queued_spin_lock_slowpath+0x939/0xc60 kernel/locking/qspinlock.c:560
       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:640
       kasan_save_stack mm/kasan/common.c:48 [inline]
       kasan_save_track+0x51/0x80 mm/kasan/common.c:68
       kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
       poison_slab_object+0xa6/0xe0 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:2106 [inline]
       slab_free mm/slub.c:4280 [inline]
       kfree+0x153/0x3a0 mm/slub.c:4390
       find_tree_dqentry+0xc3c/0xfb0 fs/quota/quota_tree.c:702
       find_tree_dqentry+0x6cd/0xfb0 fs/quota/quota_tree.c:698
       find_dqentry fs/quota/quota_tree.c:716 [inline]
       qtree_read_dquot+0x53e/0x7e0 fs/quota/quota_tree.c:736
       v2_read_dquot+0x11e/0x200 fs/quota/quota_v2.c:344
       dquot_acquire+0x194/0x680 fs/quota/dquot.c:463
       ext4_acquire_dquot+0x301/0x4c0 fs/ext4/super.c:6882
       dqget+0x772/0xeb0 fs/quota/dquot.c:977
       __dquot_initialize+0x468/0xec0 fs/quota/dquot.c:1505
       ext4_create+0xb5/0x550 fs/ext4/namei.c:2823
       lookup_open fs/namei.c:3497 [inline]
       open_last_lookups fs/namei.c:3566 [inline]
       path_openat+0x1427/0x3240 fs/namei.c:3796
       do_filp_open+0x235/0x490 fs/namei.c:3826
       do_sys_openat2+0x13e/0x1d0 fs/open.c:1406
       do_sys_open fs/open.c:1421 [inline]
       __do_sys_creat fs/open.c:1497 [inline]
       __se_sys_creat fs/open.c:1491 [inline]
       __x64_sys_creat+0x123/0x170 fs/open.c:1491
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf5/0x240 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+0x18cb/0x58e0 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:640
       kasan_save_stack mm/kasan/common.c:48 [inline]
       kasan_save_track+0x51/0x80 mm/kasan/common.c:68
       poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
       __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
       kasan_kmalloc include/linux/kasan.h:211 [inline]
       __do_kmalloc_node mm/slub.c:3966 [inline]
       __kmalloc_node+0x253/0x4e0 mm/slub.c:3973
       kmalloc_node include/linux/slab.h:648 [inline]
       bpf_map_kmalloc_node+0xd3/0x1c0 kernel/bpf/syscall.c:422
       lpm_trie_node_alloc kernel/bpf/lpm_trie.c:291 [inline]
       trie_update_elem+0x1d3/0xc10 kernel/bpf/lpm_trie.c:333
       bpf_map_update_value+0x4d5/0x540 kernel/bpf/syscall.c:203
       map_update_elem+0x53a/0x6f0 kernel/bpf/syscall.c:1641
       __sys_bpf+0x76f/0x810 kernel/bpf/syscall.c:5648
       __do_sys_bpf kernel/bpf/syscall.c:5767 [inline]
       __se_sys_bpf kernel/bpf/syscall.c:5765 [inline]
       __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5765
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xf5/0x240 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.3/5489:
 #0: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #0: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #0: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: bpf_map_update_value+0x3c4/0x540 kernel/bpf/syscall.c:202
 #1: ffff8880121cf9f8 (&trie->lock){-.-.}-{2:2}, at: trie_update_elem+0xcb/0xc10 kernel/bpf/lpm_trie.c:324

stack backtrace:
CPU: 1 PID: 5489 Comm: syz-executor.3 Not tainted 6.9.0-rc4-syzkaller-00266-g977b1ef51866 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
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+0x18cb/0x58e0 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:640
 kasan_save_stack mm/kasan/common.c:48 [inline]
 kasan_save_track+0x51/0x80 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:370 [inline]
 __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:387
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 __do_kmalloc_node mm/slub.c:3966 [inline]
 __kmalloc_node+0x253/0x4e0 mm/slub.c:3973
 kmalloc_node include/linux/slab.h:648 [inline]
 bpf_map_kmalloc_node+0xd3/0x1c0 kernel/bpf/syscall.c:422
 lpm_trie_node_alloc kernel/bpf/lpm_trie.c:291 [inline]
 trie_update_elem+0x1d3/0xc10 kernel/bpf/lpm_trie.c:333
 bpf_map_update_value+0x4d5/0x540 kernel/bpf/syscall.c:203
 map_update_elem+0x53a/0x6f0 kernel/bpf/syscall.c:1641
 __sys_bpf+0x76f/0x810 kernel/bpf/syscall.c:5648
 __do_sys_bpf kernel/bpf/syscall.c:5767 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5765 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5765
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x240 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7efe77c7dea9
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:00007efe789050c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007efe77dabf80 RCX: 00007efe77c7dea9
RDX: 0000000000000020 RSI: 00000000200002c0 RDI: 0000000000000002
RBP: 00007efe77cca4a4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007efe77dabf80 R15: 00007fffff8122a8
 </TASK>


---
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