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=17080d20980000 kernel config: https://syzkaller.appspot.com/x/.config?x=f47e5e015c177e57 dashboard link: https://syzkaller.appspot.com/bug?extid=83e7f982ca045ab4405c 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/549d1add1da9/disk-977b1ef5.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/3e8e501c8aa2/vmlinux-977b1ef5.xz kernel image: https://storage.googleapis.com/syzbot-assets/d02f7cb905b8/bzImage-977b1ef5.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+83e7f982ca045ab4405c@xxxxxxxxxxxxxxxxxxxxxxxxx ====================================================== WARNING: possible circular locking dependency detected 6.9.0-rc4-syzkaller-00266-g977b1ef51866 #0 Not tainted ------------------------------------------------------ syz-executor.0/11241 is trying to acquire lock: ffff888020a2c0d8 (&sighand->siglock){-.-.}-{2:2}, at: force_sig_info_to_task+0x68/0x580 kernel/signal.c:1334 but task is already holding lock: ffff8880b943e658 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (&rq->__lock){-.-.}-{2:2}: lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5754 _raw_spin_lock_nested+0x31/0x40 kernel/locking/spinlock.c:378 raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559 raw_spin_rq_lock kernel/sched/sched.h:1385 [inline] _raw_spin_rq_lock_irqsave kernel/sched/sched.h:1404 [inline] rq_lock_irqsave kernel/sched/sched.h:1683 [inline] class_rq_lock_irqsave_constructor kernel/sched/sched.h:1737 [inline] sched_mm_cid_exit_signals+0x17b/0x4b0 kernel/sched/core.c:12005 exit_signals+0x2a1/0x5c0 kernel/signal.c:3016 do_exit+0x6a8/0x27e0 kernel/exit.c:837 __do_sys_exit kernel/exit.c:994 [inline] __se_sys_exit kernel/exit.c:992 [inline] __pfx___ia32_sys_exit+0x0/0x10 kernel/exit.c:992 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 (&sighand->siglock){-.-.}-{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 force_sig_info_to_task+0x68/0x580 kernel/signal.c:1334 force_sig_fault_to_task kernel/signal.c:1733 [inline] force_sig_fault+0x12c/0x1d0 kernel/signal.c:1738 __bad_area_nosemaphore+0x127/0x780 arch/x86/mm/fault.c:814 handle_page_fault arch/x86/mm/fault.c:1505 [inline] exc_page_fault+0x612/0x8e0 arch/x86/mm/fault.c:1563 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 strncpy_from_user+0x2c6/0x2f0 lib/strncpy_from_user.c:138 strncpy_from_user_nofault+0x71/0x140 mm/maccess.c:186 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:216 [inline] ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:311 [inline] bpf_probe_read_compat_str+0xe9/0x180 kernel/trace/bpf_trace.c:307 bpf_prog_e42f6260c1b72fb3+0x3d/0x3f 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_run4+0x25a/0x490 kernel/trace/bpf_trace.c:2422 __traceiter_sched_switch+0x98/0xd0 include/trace/events/sched.h:222 trace_sched_switch include/trace/events/sched.h:222 [inline] __schedule+0x2535/0x4a00 kernel/sched/core.c:6743 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7068 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 force_sig_fault+0x0/0x1d0 __bad_area_nosemaphore+0x127/0x780 arch/x86/mm/fault.c:814 handle_page_fault arch/x86/mm/fault.c:1505 [inline] exc_page_fault+0x612/0x8e0 arch/x86/mm/fault.c:1563 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 __put_user_handle_exception+0x0/0x10 __do_sys_gettimeofday kernel/time/time.c:147 [inline] __se_sys_gettimeofday+0xd9/0x240 kernel/time/time.c:140 emulate_vsyscall+0xe23/0x1290 arch/x86/entry/vsyscall/vsyscall_64.c:247 do_user_addr_fault arch/x86/mm/fault.c:1346 [inline] handle_page_fault arch/x86/mm/fault.c:1505 [inline] exc_page_fault+0x160/0x8e0 arch/x86/mm/fault.c:1563 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 _end+0x6a9da000/0x0 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&rq->__lock); lock(&sighand->siglock); lock(&rq->__lock); lock(&sighand->siglock); *** DEADLOCK *** 2 locks held by syz-executor.0/11241: #0: ffff8880b943e658 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2a/0x140 kernel/sched/core.c:559 #1: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:329 [inline] #1: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:781 [inline] #1: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: __bpf_trace_run kernel/trace/bpf_trace.c:2380 [inline] #1: ffffffff8e334d20 (rcu_read_lock){....}-{1:2}, at: bpf_trace_run4+0x16e/0x490 kernel/trace/bpf_trace.c:2422 stack backtrace: CPU: 0 PID: 11241 Comm: syz-executor.0 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 force_sig_info_to_task+0x68/0x580 kernel/signal.c:1334 force_sig_fault_to_task kernel/signal.c:1733 [inline] force_sig_fault+0x12c/0x1d0 kernel/signal.c:1738 __bad_area_nosemaphore+0x127/0x780 arch/x86/mm/fault.c:814 handle_page_fault arch/x86/mm/fault.c:1505 [inline] exc_page_fault+0x612/0x8e0 arch/x86/mm/fault.c:1563 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0010:do_strncpy_from_user lib/strncpy_from_user.c:72 [inline] RIP: 0010:strncpy_from_user+0x2c6/0x2f0 lib/strncpy_from_user.c:139 Code: cc cc cc cc e8 ab 95 b6 fc 45 31 ed eb e0 e8 a1 95 b6 fc 49 c7 c5 f2 ff ff ff eb d2 e8 93 95 b6 fc 49 c7 c5 f2 ff ff ff eb c4 <f3> 0f 1e fa e8 81 95 b6 fc eb a1 f3 0f 1e fa e8 76 95 b6 fc 4d 29 RSP: 0018:ffffc90009f9f5e0 EFLAGS: 00050046 RAX: 0000000000000002 RBX: ffff8880795c3584 RCX: ffff8880795c1e00 RDX: ffffc90004bf1000 RSI: 0000000000000001 RDI: 0000000000000000 RBP: 0000000000000001 R08: ffffffff84df6a34 R09: ffffffff82056cb7 R10: 0000000000000003 R11: ffff8880795c1e00 R12: 0000000000000000 R13: 0000000000000000 R14: ffffc90009f9f6a8 R15: 0000000000000000 strncpy_from_user_nofault+0x71/0x140 mm/maccess.c:186 bpf_probe_read_user_str_common kernel/trace/bpf_trace.c:216 [inline] ____bpf_probe_read_compat_str kernel/trace/bpf_trace.c:311 [inline] bpf_probe_read_compat_str+0xe9/0x180 kernel/trace/bpf_trace.c:307 bpf_prog_e42f6260c1b72fb3+0x3d/0x3f 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_run4+0x25a/0x490 kernel/trace/bpf_trace.c:2422 __traceiter_sched_switch+0x98/0xd0 include/trace/events/sched.h:222 trace_sched_switch include/trace/events/sched.h:222 [inline] __schedule+0x2535/0x4a00 kernel/sched/core.c:6743 preempt_schedule_irq+0xfb/0x1c0 kernel/sched/core.c:7068 irqentry_exit+0x5e/0x90 kernel/entry/common.c:354 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702 RIP: 0010:force_sig_fault+0x0/0x1d0 kernel/signal.c:1737 Code: 9a 00 e9 31 ff ff ff e8 1e 7e 1a 0a 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 <f3> 0f 1e fa 55 48 89 e5 41 57 41 56 41 55 41 54 53 48 83 e4 e0 48 RSP: 0018:ffffc90009f9fb78 EFLAGS: 00000286 RAX: ffffffff8141f9d7 RBX: 0000000000000000 RCX: 0000000000040000 RDX: 0000000000000019 RSI: 0000000000000001 RDI: 000000000000000b RBP: ffffc90009f9fc78 R08: ffffffff8141f976 R09: ffffffff81423712 R10: 0000000000000014 R11: ffff8880795c1e00 R12: dffffc0000000000 R13: ffffc90009f9fd70 R14: 1ffff920013f3fae R15: 0000000000000002 __bad_area_nosemaphore+0x127/0x780 arch/x86/mm/fault.c:814 handle_page_fault arch/x86/mm/fault.c:1505 [inline] exc_page_fault+0x612/0x8e0 arch/x86/mm/fault.c:1563 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0010:__put_user_handle_exception+0x0/0x10 arch/x86/lib/putuser.S:125 Code: 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 01 cb 48 89 01 31 c9 0f 01 ca c3 cc cc cc cc 66 2e 0f 1f 84 00 00 00 00 00 66 90 <0f> 01 ca b9 f2 ff ff ff c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 RSP: 0018:ffffc90009f9fd98 EFLAGS: 00050202 RAX: 000000006624d6a7 RBX: 0000000000000000 RCX: 0000000000000019 RDX: 0000000000000000 RSI: ffffffff8bcaca20 RDI: ffffffff8c1eb160 RBP: ffffc90009f9fe50 R08: ffffffff8fa7b6af R09: 1ffffffff1f4f6d5 R10: dffffc0000000000 R11: fffffbfff1f4f6d6 R12: ffffc90009f9fde0 R13: dffffc0000000000 R14: 1ffff920013f3fb8 R15: 0000000000000019 __do_sys_gettimeofday kernel/time/time.c:147 [inline] __se_sys_gettimeofday+0xd9/0x240 kernel/time/time.c:140 emulate_vsyscall+0xe23/0x1290 arch/x86/entry/vsyscall/vsyscall_64.c:247 do_user_addr_fault arch/x86/mm/fault.c:1346 [inline] handle_page_fault arch/x86/mm/fault.c:1505 [inline] exc_page_fault+0x160/0x8e0 arch/x86/mm/fault.c:1563 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623 RIP: 0033:_end+0x6a9da000/0x0 Code: Unable to access opcode bytes at 0xffffffffff5fffd6. RSP: 002b:00007f9364a35b38 EFLAGS: 00010246 RAX: ffffffffffffffda RBX: 00007f9363dabf80 RCX: 00007f9363c7dea9 RDX: 00007f9364a35b40 RSI: 00007f9364a35c70 RDI: 0000000000000019 RBP: 00007f9363cca4a4 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000007 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f9363dabf80 R15: 00007ffc4b734e88 </TASK> ---------------- Code disassembly (best guess): 0: cc int3 1: cc int3 2: cc int3 3: cc int3 4: e8 ab 95 b6 fc call 0xfcb695b4 9: 45 31 ed xor %r13d,%r13d c: eb e0 jmp 0xffffffee e: e8 a1 95 b6 fc call 0xfcb695b4 13: 49 c7 c5 f2 ff ff ff mov $0xfffffffffffffff2,%r13 1a: eb d2 jmp 0xffffffee 1c: e8 93 95 b6 fc call 0xfcb695b4 21: 49 c7 c5 f2 ff ff ff mov $0xfffffffffffffff2,%r13 28: eb c4 jmp 0xffffffee * 2a: f3 0f 1e fa endbr64 <-- trapping instruction 2e: e8 81 95 b6 fc call 0xfcb695b4 33: eb a1 jmp 0xffffffd6 35: f3 0f 1e fa endbr64 39: e8 76 95 b6 fc call 0xfcb695b4 3e: 4d rex.WRB 3f: 29 .byte 0x29 --- 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
