Message-ID: <66ffd428.050a0220.49194.048a.GAE@google.com>
Date: Fri, 04 Oct 2024 04:40:24 -0700
From: syzbot <syzbot+5a878c984150fad34185@...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, netdev@...r.kernel.org, 
	sdf@...ichev.me, song@...nel.org, syzkaller-bugs@...glegroups.com, 
	yonghong.song@...ux.dev
Subject: [syzbot] [bpf?] possible deadlock in __put_partials

Hello,

syzbot found the following issue on:

HEAD commit:    99a648c951ba selftests/bpf: Verify that sync_linked_regs p..
git tree:       bpf
console output: https://syzkaller.appspot.com/x/log.txt?x=1668bd07980000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d3e39725ec0dfcbc
dashboard link: https://syzkaller.appspot.com/bug?extid=5a878c984150fad34185
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/e45f24c2d262/disk-99a648c9.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/48ad218fc65c/vmlinux-99a648c9.xz
kernel image: https://storage.googleapis.com/syzbot-assets/691b40913107/bzImage-99a648c9.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+5a878c984150fad34185@...kaller.appspotmail.com

tun0: tun_chr_ioctl cmd 1074025681
======================================================
WARNING: possible circular locking dependency detected
6.11.0-syzkaller-10550-g99a648c951ba #0 Not tainted
------------------------------------------------------
syz.0.924/9009 is trying to acquire lock:
ffff8881404006d8 (&n->list_lock){-.-.}-{2:2}, at: __put_partials+0x61/0x130 mm/slub.c:3126

but task is already holding lock:
ffff8880758dda00 (&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:5822
       __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
       0xffffffffa00021b3
       bpf_dispatcher_nop_func include/linux/bpf.h:1257 [inline]
       __bpf_prog_run include/linux/filter.h:701 [inline]
       bpf_prog_run include/linux/filter.h:708 [inline]
       __bpf_trace_run kernel/trace/bpf_trace.c:2318 [inline]
       bpf_trace_run2+0x2ec/0x540 kernel/trace/bpf_trace.c:2359
       trace_contention_end+0x114/0x140 include/trace/events/lock.h:122
       __pv_queued_spin_lock_slowpath+0xb7e/0xdb0 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
       __put_partials+0x61/0x130 mm/slub.c:3126
       put_cpu_partial+0x17c/0x250 mm/slub.c:3221
       __slab_free+0x2ea/0x3d0 mm/slub.c:4450
       qlink_free mm/kasan/quarantine.c:163 [inline]
       qlist_free_all+0x9a/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:329
       kasan_slab_alloc include/linux/kasan.h:247 [inline]
       slab_post_alloc_hook mm/slub.c:4086 [inline]
       slab_alloc_node mm/slub.c:4135 [inline]
       kmem_cache_alloc_node_noprof+0x16b/0x320 mm/slub.c:4187
       perf_event_alloc+0x166/0x2310 kernel/events/core.c:12147
       __do_sys_perf_event_open kernel/events/core.c:12767 [inline]
       __se_sys_perf_event_open+0xb1f/0x3870 kernel/events/core.c:12658
       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 (&n->list_lock){-.-.}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:3158 [inline]
       check_prevs_add kernel/locking/lockdep.c:3277 [inline]
       validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
       __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
       lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
       __put_partials+0x61/0x130 mm/slub.c:3126
       ___slab_alloc+0x4f7/0x14b0 mm/slub.c:3776
       __slab_alloc+0x58/0xa0 mm/slub.c:3909
       __slab_alloc_node mm/slub.c:3962 [inline]
       slab_alloc_node mm/slub.c:4123 [inline]
       __do_kmalloc_node mm/slub.c:4264 [inline]
       __kmalloc_node_noprof+0x286/0x440 mm/slub.c:4271
       kmalloc_array_node_noprof include/linux/slab.h:995 [inline]
       alloc_slab_obj_exts mm/slub.c:1969 [inline]
       account_slab mm/slub.c:2542 [inline]
       allocate_slab+0xb6/0x2f0 mm/slub.c:2597
       new_slab mm/slub.c:2632 [inline]
       ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3819
       __slab_alloc+0x58/0xa0 mm/slub.c:3909
       __slab_alloc_node mm/slub.c:3962 [inline]
       slab_alloc_node mm/slub.c:4123 [inline]
       __do_kmalloc_node mm/slub.c:4264 [inline]
       __kmalloc_node_noprof+0x286/0x440 mm/slub.c:4271
       kmalloc_node_noprof include/linux/slab.h:905 [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+0x4d3/0x540 kernel/bpf/syscall.c:203
       generic_map_update_batch+0x60d/0x900 kernel/bpf/syscall.c:1849
       bpf_map_do_batch+0x39a/0x660 kernel/bpf/syscall.c:5143
       __sys_bpf+0x377/0x810
       __do_sys_bpf kernel/bpf/syscall.c:5741 [inline]
       __se_sys_bpf kernel/bpf/syscall.c:5739 [inline]
       __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5739
       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(&n->list_lock);
                               lock(&trie->lock);
  lock(&n->list_lock);

 *** DEADLOCK ***

2 locks held by syz.0.924/9009:
 #0: ffffffff8e937ee0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
 #0: ffffffff8e937ee0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
 #0: ffffffff8e937ee0 (rcu_read_lock){....}-{1:2}, at: bpf_map_update_value+0x3c4/0x540 kernel/bpf/syscall.c:202
 #1: ffff8880758dda00 (&trie->lock){-.-.}-{2:2}, at: trie_update_elem+0xc8/0xc00 kernel/bpf/lpm_trie.c:333

stack backtrace:
CPU: 0 UID: 0 PID: 9009 Comm: syz.0.924 Not tainted 6.11.0-syzkaller-10550-g99a648c951ba #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_circular_bug+0x13a/0x1b0 kernel/locking/lockdep.c:2074
 check_noncircular+0x36a/0x4a0 kernel/locking/lockdep.c:2203
 check_prev_add kernel/locking/lockdep.c:3158 [inline]
 check_prevs_add kernel/locking/lockdep.c:3277 [inline]
 validate_chain+0x18ef/0x5920 kernel/locking/lockdep.c:3901
 __lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5199
 lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5822
 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
 _raw_spin_lock_irqsave+0xd5/0x120 kernel/locking/spinlock.c:162
 __put_partials+0x61/0x130 mm/slub.c:3126
 ___slab_alloc+0x4f7/0x14b0 mm/slub.c:3776
 __slab_alloc+0x58/0xa0 mm/slub.c:3909
 __slab_alloc_node mm/slub.c:3962 [inline]
 slab_alloc_node mm/slub.c:4123 [inline]
 __do_kmalloc_node mm/slub.c:4264 [inline]
 __kmalloc_node_noprof+0x286/0x440 mm/slub.c:4271
 kmalloc_array_node_noprof include/linux/slab.h:995 [inline]
 alloc_slab_obj_exts mm/slub.c:1969 [inline]
 account_slab mm/slub.c:2542 [inline]
 allocate_slab+0xb6/0x2f0 mm/slub.c:2597
 new_slab mm/slub.c:2632 [inline]
 ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3819
 __slab_alloc+0x58/0xa0 mm/slub.c:3909
 __slab_alloc_node mm/slub.c:3962 [inline]
 slab_alloc_node mm/slub.c:4123 [inline]
 __do_kmalloc_node mm/slub.c:4264 [inline]
 __kmalloc_node_noprof+0x286/0x440 mm/slub.c:4271
 kmalloc_node_noprof include/linux/slab.h:905 [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+0x4d3/0x540 kernel/bpf/syscall.c:203
 generic_map_update_batch+0x60d/0x900 kernel/bpf/syscall.c:1849
 bpf_map_do_batch+0x39a/0x660 kernel/bpf/syscall.c:5143
 __sys_bpf+0x377/0x810
 __do_sys_bpf kernel/bpf/syscall.c:5741 [inline]
 __se_sys_bpf kernel/bpf/syscall.c:5739 [inline]
 __x64_sys_bpf+0x7c/0x90 kernel/bpf/syscall.c:5739
 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: 0033:0x7fea6a97dff9
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:00007fea6b756038 EFLAGS: 00000246 ORIG_RAX: 0000000000000141
RAX: ffffffffffffffda RBX: 00007fea6ab35f80 RCX: 00007fea6a97dff9
RDX: 0000000000000038 RSI: 0000000020000480 RDI: 000000000000001a
RBP: 00007fea6a9f0296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fea6ab35f80 R15: 00007ffd21039768
 </TASK>


---
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