Hello, syzbot found the following issue on: HEAD commit: e67572cd2204 Linux 6.9-rc6 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16ec5c40980000 kernel config: https://syzkaller.appspot.com/x/.config?x=d2f00edef461175 dashboard link: https://syzkaller.appspot.com/bug?extid=fa04eb8a56fd923fc5d8 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/7ece3eebb82c/disk-e67572cd.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/81b1e26c57c9/vmlinux-e67572cd.xz kernel image: https://storage.googleapis.com/syzbot-assets/be9561f066e4/bzImage-e67572cd.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+fa04eb8a56fd923fc5d8@xxxxxxxxxxxxxxxxxxxxxxxxx ============================= WARNING: suspicious RCU usage 6.9.0-rc6-syzkaller #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 10 locks held by syz-executor.1/8017: #0: ffffffff8e3df430 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mmap kernel/fork.c:637 [inline] #0: ffffffff8e3df430 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1688 [inline] #0: ffffffff8e3df430 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x275/0x2180 kernel/fork.c:1737 #1: ffff888078cbea20 (&mm->mmap_lock){++++}-{3:3}, at: mmap_write_lock_killable include/linux/mmap_lock.h:124 [inline] #1: ffff888078cbea20 (&mm->mmap_lock){++++}-{3:3}, at: dup_mmap kernel/fork.c:638 [inline] #1: ffff888078cbea20 (&mm->mmap_lock){++++}-{3:3}, at: dup_mm kernel/fork.c:1688 [inline] #1: ffff888078cbea20 (&mm->mmap_lock){++++}-{3:3}, at: copy_mm+0x295/0x2180 kernel/fork.c:1737 #2: ffff88806a945720 (&mm->mmap_lock/1){+.+.}-{3:3}, at: mmap_write_lock_nested include/linux/mmap_lock.h:115 [inline] #2: ffff88806a945720 (&mm->mmap_lock/1){+.+.}-{3:3}, at: dup_mmap kernel/fork.c:647 [inline] #2: ffff88806a945720 (&mm->mmap_lock/1){+.+.}-{3:3}, at: dup_mm kernel/fork.c:1688 [inline] #2: ffff88806a945720 (&mm->mmap_lock/1){+.+.}-{3:3}, at: copy_mm+0x3d1/0x2180 kernel/fork.c:1737 #3: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #3: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #3: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: __pte_offset_map+0x82/0x380 mm/pgtable-generic.c:285 #4: ffff88802db9a798 (ptlock_ptr(ptdesc)#2){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #4: ffff88802db9a798 (ptlock_ptr(ptdesc)#2){+.+.}-{2:2}, at: __pte_offset_map_lock+0x1ba/0x300 mm/pgtable-generic.c:373 #5: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #5: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #5: ffffffff8e334da0 (rcu_read_lock){....}-{1:2}, at: __pte_offset_map+0x82/0x380 mm/pgtable-generic.c:285 #6: ffff8880298631f8 (ptlock_ptr(ptdesc)#2/1){+.+.}-{2:2}, at: copy_pte_range mm/memory.c:1103 [inline] #6: ffff8880298631f8 (ptlock_ptr(ptdesc)#2/1){+.+.}-{2:2}, at: copy_pmd_range mm/memory.c:1238 [inline] #6: ffff8880298631f8 (ptlock_ptr(ptdesc)#2/1){+.+.}-{2:2}, at: copy_pud_range mm/memory.c:1275 [inline] #6: ffff8880298631f8 (ptlock_ptr(ptdesc)#2/1){+.+.}-{2:2}, at: copy_p4d_range mm/memory.c:1299 [inline] #6: ffff8880298631f8 (ptlock_ptr(ptdesc)#2/1){+.+.}-{2:2}, at: copy_page_range+0x11c7/0x5b00 mm/memory.c:1397 #7: ffffffff8e334d20 (rcu_read_lock_sched){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #7: ffffffff8e334d20 (rcu_read_lock_sched){....}-{1:2}, at: rcu_read_lock_sched include/linux/rcupdate.h:873 [inline] #7: ffffffff8e334d20 (rcu_read_lock_sched){....}-{1:2}, at: pfn_valid+0xf6/0x440 include/linux/mmzone.h:2019 #8: ffffc90000a08c00 ((&p->forward_delay_timer)){+.-.}-{0:0}, at: call_timer_fn+0xc0/0x650 kernel/time/timer.c:1790 #9: ffff88807b56ccb8 (&br->lock){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline] #9: ffff88807b56ccb8 (&br->lock){+.-.}-{2:2}, at: br_forward_delay_timer_expired+0x50/0x440 net/bridge/br_stp_timer.c:86 stack backtrace: CPU: 1 PID: 8017 Comm: syz-executor.1 Not tainted 6.9.0-rc6-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024 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+0x1ea/0x650 net/bridge/br_mst.c:105 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:1793 expire_timers kernel/time/timer.c:1844 [inline] __run_timers kernel/time/timer.c:2418 [inline] __run_timer_base+0x66a/0x8e0 kernel/time/timer.c:2429 run_timer_base kernel/time/timer.c:2438 [inline] run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2448 __do_softirq+0x2c6/0x980 kernel/softirq.c:554 invoke_softirq kernel/softirq.c:428 [inline] __irq_exit_rcu+0xf2/0x1c0 kernel/softirq.c:633 irq_exit_rcu+0x9/0x30 kernel/softirq.c:645 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:lock_acquire+0x264/0x550 kernel/locking/lockdep.c:5758 Code: 2b 00 74 08 4c 89 f7 e8 ba d1 84 00 f6 44 24 61 02 0f 85 85 01 00 00 41 f7 c7 00 02 00 00 74 01 fb 48 c7 44 24 40 0e 36 e0 45 <4b> c7 44 25 00 00 00 00 00 43 c7 44 25 09 00 00 00 00 43 c7 44 25 RSP: 0018:ffffc90013657100 EFLAGS: 00000206 RAX: 0000000000000001 RBX: 1ffff920026cae2c RCX: 0000000000000001 RDX: dffffc0000000000 RSI: ffffffff8bcaca00 RDI: ffffffff8c1eaa60 RBP: ffffc90013657260 R08: ffffffff92efe507 R09: 1ffffffff25dfca0 R10: dffffc0000000000 R11: fffffbfff25dfca1 R12: 1ffff920026cae28 R13: dffffc0000000000 R14: ffffc90013657160 R15: 0000000000000246 rcu_lock_acquire include/linux/rcupdate.h:329 [inline] rcu_read_lock_sched include/linux/rcupdate.h:873 [inline] pfn_valid+0x113/0x440 include/linux/mmzone.h:2019 page_table_check_set+0x25/0x700 mm/page_table_check.c:105 __page_table_check_ptes_set+0x220/0x280 mm/page_table_check.c:196 page_table_check_ptes_set include/linux/page_table_check.h:74 [inline] set_ptes include/linux/pgtable.h:267 [inline] __copy_present_ptes mm/memory.c:953 [inline] copy_present_ptes mm/memory.c:1036 [inline] copy_pte_range mm/memory.c:1151 [inline] copy_pmd_range mm/memory.c:1238 [inline] copy_pud_range mm/memory.c:1275 [inline] copy_p4d_range mm/memory.c:1299 [inline] copy_page_range+0x3d98/0x5b00 mm/memory.c:1397 dup_mmap kernel/fork.c:751 [inline] dup_mm kernel/fork.c:1688 [inline] copy_mm+0x1321/0x2180 kernel/fork.c:1737 copy_process+0x187a/0x3df0 kernel/fork.c:2390 kernel_clone+0x223/0x870 kernel/fork.c:2797 __do_sys_clone kernel/fork.c:2940 [inline] __se_sys_clone kernel/fork.c:2924 [inline] __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2924 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: 0033:0x7ff5bc07aed3 Code: 1f 84 00 00 00 00 00 64 48 8b 04 25 10 00 00 00 45 31 c0 31 d2 31 f6 bf 11 00 20 01 4c 8d 90 d0 02 00 00 b8 38 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 89 c2 85 c0 75 2c 64 48 8b 04 25 10 00 00 RSP: 002b:00007ffd2ed6ec68 EFLAGS: 00000246 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff5bc07aed3 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000001200011 RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: 00005555798ad750 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000001 R15: 0000000000000001 </TASK> bridge0: port 1(bridge_slave_0) entered learning state bridge0: port 2(bridge_slave_1) entered learning state ---------------- Code disassembly (best guess): 0: 2b 00 sub (%rax),%eax 2: 74 08 je 0xc 4: 4c 89 f7 mov %r14,%rdi 7: e8 ba d1 84 00 call 0x84d1c6 c: f6 44 24 61 02 testb $0x2,0x61(%rsp) 11: 0f 85 85 01 00 00 jne 0x19c 17: 41 f7 c7 00 02 00 00 test $0x200,%r15d 1e: 74 01 je 0x21 20: fb sti 21: 48 c7 44 24 40 0e 36 movq $0x45e0360e,0x40(%rsp) 28: e0 45 * 2a: 4b c7 44 25 00 00 00 movq $0x0,0x0(%r13,%r12,1) <-- trapping instruction 31: 00 00 33: 43 c7 44 25 09 00 00 movl $0x0,0x9(%r13,%r12,1) 3a: 00 00 3c: 43 rex.XB 3d: c7 .byte 0xc7 3e: 44 rex.R 3f: 25 .byte 0x25 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
