syzbot


WARNING: suspicious RCU usage in br_mst_set_state (2)

Status: upstream: reported on 2024/06/08 17:29
Subsystems: net
[Documentation on labels]
Reported-by: syzbot+9bbe2de1bc9d470eb5fe@syzkaller.appspotmail.com
Fix commit: 546ceb1dfdac net: bridge: mst: fix suspicious rcu usage in br_mst_set_state 36c92936e868 net: bridge: mst: pass vlan group directly to br_mst_vlan_set_state
Patched on: [ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-upstream-gce-leak ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-linux-next-kasan-gce-root ci2-upstream-fs ci2-upstream-kcsan-gce ci2-upstream-net-next-test-gce ci2-upstream-usb], missing on: [ci-qemu-native-arm64-kvm ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-riscv64 ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce]
First crash: 10d, last: 1d06h
Discussions (2)
Title Replies (including bot) Last reply
[PATCH net 0/2] net: bridge: mst: fix suspicious rcu usage warning 3 (3) 2024/06/09 10:36
[syzbot] [net?] WARNING: suspicious RCU usage in br_mst_set_state (2) 1 (2) 2024/06/08 18:19
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream WARNING: suspicious RCU usage in br_mst_set_state bridge 45 12d 46d 26/27 fixed on 2024/06/05 13:52
linux-6.1 WARNING: suspicious RCU usage in br_mst_set_state 1 40d 40d 0/3 upstream: reported on 2024/05/09 03:44

Sample crash report:
=============================
WARNING: suspicious RCU usage
6.10.0-rc2-syzkaller-00235-g8a92980606e3 #0 Not tainted
-----------------------------
net/bridge/br_private.h:1599 suspicious rcu_dereference_protected() usage!

other info that might help us debug this:


rcu_scheduler_active = 2, debug_locks = 1
4 locks held by syz-executor.1/5374:
 #0: ffff888022d50b18 (&mm->mmap_lock){++++}-{3:3}, at: mmap_read_lock include/linux/mmap_lock.h:144 [inline]
 #0: ffff888022d50b18 (&mm->mmap_lock){++++}-{3:3}, at: __mm_populate+0x1b0/0x460 mm/gup.c:2111
 #1: ffffc90000a18c00 ((&p->forward_delay_timer)){+.-.}-{0:0}, at: call_timer_fn+0xc0/0x650 kernel/time/timer.c:1789
 #2: ffff88805fb2ccb8 (&br->lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
 #2: ffff88805fb2ccb8 (&br->lock){+.-.}-{2:2}, at: br_forward_delay_timer_expired+0x50/0x440 net/bridge/br_stp_timer.c:86
 #3: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline]
 #3: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline]
 #3: ffffffff8e333fa0 (rcu_read_lock){....}-{1:2}, at: br_mst_set_state+0x171/0x7a0 net/bridge/br_mst.c:105

stack backtrace:
CPU: 1 PID: 5374 Comm: syz-executor.1 Not tainted 6.10.0-rc2-syzkaller-00235-g8a92980606e3 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/02/2024
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:114
 lockdep_rcu_suspicious+0x221/0x340 kernel/locking/lockdep.c:6712
 nbp_vlan_group net/bridge/br_private.h:1599 [inline]
 br_mst_set_state+0x29e/0x7a0 net/bridge/br_mst.c:106
 br_set_state+0x28a/0x7b0 net/bridge/br_stp.c:47
 br_forward_delay_timer_expired+0x176/0x440 net/bridge/br_stp_timer.c:88
 call_timer_fn+0x18e/0x650 kernel/time/timer.c:1792
 expire_timers kernel/time/timer.c:1843 [inline]
 __run_timers kernel/time/timer.c:2417 [inline]
 __run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2428
 run_timer_base kernel/time/timer.c:2437 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2447
 handle_softirqs+0x2c4/0x970 kernel/softirq.c:554
 __do_softirq kernel/softirq.c:588 [inline]
 invoke_softirq kernel/softirq.c:428 [inline]
 __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:649
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
 sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043
 </IRQ>
 <TASK>
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:87 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:104 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:129 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:161 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0x86/0x290 mm/kasan/generic.c:189
Code: 00 fc ff df 4f 8d 3c 31 4c 89 fd 4c 29 dd 48 83 fd 10 7f 29 48 85 ed 0f 84 3e 01 00 00 4c 89 cd 48 f7 d5 48 01 dd 41 80 3b 00 <0f> 85 c9 01 00 00 49 ff c3 48 ff c5 75 ee e9 1e 01 00 00 45 89 dc
RSP: 0018:ffffc90004beec90 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 1ffff9200097dd9c RCX: ffffffff8173cb88
RDX: 0000000000000001 RSI: 0000000000000004 RDI: ffffc90004beece0
RBP: ffffffffffffffff R08: ffffc90004beece3 R09: 1ffff9200097dd9c
R10: dffffc0000000000 R11: fffff5200097dd9c R12: 1ffff9200097dd98
R13: ffff8880b9544700 R14: dffffc0000000001 R15: fffff5200097dd9d
 instrument_atomic_read_write include/linux/instrumented.h:96 [inline]
 atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1301 [inline]
 queued_spin_trylock include/asm-generic/qspinlock.h:97 [inline]
 do_raw_spin_trylock+0xc8/0x1f0 kernel/locking/spinlock_debug.c:123
 __raw_spin_trylock include/linux/spinlock_api_smp.h:89 [inline]
 _raw_spin_trylock+0x20/0x80 kernel/locking/spinlock.c:138
 spin_trylock include/linux/spinlock.h:361 [inline]
 rmqueue_pcplist mm/page_alloc.c:2940 [inline]
 rmqueue mm/page_alloc.c:2990 [inline]
 get_page_from_freelist+0x79f/0x2ee0 mm/page_alloc.c:3399
 __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4660
 alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
 shmem_alloc_folio mm/shmem.c:1628 [inline]
 shmem_alloc_and_add_folio+0x24d/0xdb0 mm/shmem.c:1668
 shmem_get_folio_gfp+0x82d/0x1f50 mm/shmem.c:2055
 shmem_fault+0x252/0x6f0 mm/shmem.c:2255
 __do_fault+0x135/0x460 mm/memory.c:4562
 do_read_fault mm/memory.c:4926 [inline]
 do_fault mm/memory.c:5056 [inline]
 do_pte_missing mm/memory.c:3903 [inline]
 handle_pte_fault+0x3d8d/0x7130 mm/memory.c:5380
 __handle_mm_fault mm/memory.c:5523 [inline]
 handle_mm_fault+0xfb0/0x19d0 mm/memory.c:5688
 faultin_page mm/gup.c:1290 [inline]
 __get_user_pages+0x6ef/0x1590 mm/gup.c:1589
 populate_vma_page_range+0x264/0x330 mm/gup.c:2029
 __mm_populate+0x27a/0x460 mm/gup.c:2132
 mm_populate include/linux/mm.h:3464 [inline]
 vm_mmap_pgoff+0x2c3/0x3d0 mm/util.c:578
 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: 0033:0x7f1686c7cf69
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:00007f168799f0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 00007f1686db3f80 RCX: 00007f1686c7cf69
RDX: b635773f06ebbeee RSI: 0000000000b36000 RDI: 0000000020000000
RBP: 00007f1686cda6fe R08: ffffffffffffffff R09: 0000000000000000
R10: 0000000000008031 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f1686db3f80 R15: 00007ffd6eb2ca48
 </TASK>
bridge0: port 2(bridge_slave_1) entered learning state
----------------
Code disassembly (best guess), 3 bytes skipped:
   0:	df 4f 8d             	fisttps -0x73(%rdi)
   3:	3c 31                	cmp    $0x31,%al
   5:	4c 89 fd             	mov    %r15,%rbp
   8:	4c 29 dd             	sub    %r11,%rbp
   b:	48 83 fd 10          	cmp    $0x10,%rbp
   f:	7f 29                	jg     0x3a
  11:	48 85 ed             	test   %rbp,%rbp
  14:	0f 84 3e 01 00 00    	je     0x158
  1a:	4c 89 cd             	mov    %r9,%rbp
  1d:	48 f7 d5             	not    %rbp
  20:	48 01 dd             	add    %rbx,%rbp
  23:	41 80 3b 00          	cmpb   $0x0,(%r11)
* 27:	0f 85 c9 01 00 00    	jne    0x1f6 <-- trapping instruction
  2d:	49 ff c3             	inc    %r11
  30:	48 ff c5             	inc    %rbp
  33:	75 ee                	jne    0x23
  35:	e9 1e 01 00 00       	jmp    0x158
  3a:	45 89 dc             	mov    %r11d,%r12d

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/06/07 19:09 upstream 8a92980606e3 82c05ab8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-smack-root WARNING: suspicious RCU usage in br_mst_set_state
2024/06/07 18:24 upstream 8a92980606e3 82c05ab8 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root WARNING: suspicious RCU usage in br_mst_set_state
2024/06/10 14:38 net 5add2f728846 048c640a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-net-this-kasan-gce WARNING: suspicious RCU usage in br_mst_set_state
2024/06/17 06:10 linux-next a957267fa7e9 f429ab00 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root WARNING: suspicious RCU usage in br_mst_set_state
* Struck through repros no longer work on HEAD.