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2026 00:28:31 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a7ec39f.5b0d2c79.2ef4ef.0002.GAE@google.com> Subject: [syzbot] [kernel?] general protection fault in timers_dead_cpu From: syzbot To: linux-kernel@vger.kernel.org, peterz@infradead.org, syzkaller-bugs@googlegroups.com, tglx@kernel.org Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: db2ddb871435 Linux 7.2-rc7 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=14ec2149580000 kernel config: https://syzkaller.appspot.com/x/.config?x=c44651ea7dd2f307 dashboard link: https://syzkaller.appspot.com/bug?extid=74de56995244fe32ffe2 compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=12ec2149580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=16d962c6580000 Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-db2ddb87.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/698def9fcf7a/vmlinux-db2ddb87.xz kernel image: https://storage.googleapis.com/syzbot-assets/fd8b6091a563/bzImage-db2ddb87.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+74de56995244fe32ffe2@syzkaller.appspotmail.com smpboot: CPU 1 is now offline Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 2 UID: 0 PID: 6237 Comm: syz.2.92 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 RIP: 0010:__hlist_del include/linux/list.h:1029 [inline] RIP: 0010:detach_timer kernel/time/timer.c:891 [inline] RIP: 0010:migrate_timer_list kernel/time/timer.c:2493 [inline] RIP: 0010:timers_dead_cpu+0x326/0x860 kernel/time/timer.c:2541 Code: 0f 85 0c 04 00 00 48 8d 7b 08 48 8b 2b 48 89 f8 48 c1 e8 03 42 80 3c 38 00 0f 85 df 03 00 00 48 8b 43 08 48 89 c2 48 c1 ea 03 <42> 80 3c 3a 00 0f 85 b4 03 00 00 48 89 28 48 89 04 24 48 85 ed 74 RSP: 0018:ffffc900040078c0 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffff88806a523440 RCX: ffffffff81f5d5d8 RDX: 0000000000000000 RSI: ffffffff81f5d420 RDI: ffff88806a523448 RBP: dead000000000122 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff88806a5258d0 R13: ffffed100d4a4b1a R14: ffff88806a6251c0 R15: dffffc0000000000 FS: 00007f01d4dfe6c0(0000) GS:ffff8880d5fec000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9c1ca70000 CR3: 000000003de42000 CR4: 0000000000352ef0 Call Trace: cpuhp_invoke_callback+0x3b4/0x9a0 kernel/cpu.c:194 __cpuhp_invoke_callback_range+0x158/0x1d0 kernel/cpu.c:972 cpuhp_invoke_callback_range kernel/cpu.c:996 [inline] cpuhp_down_callbacks kernel/cpu.c:1386 [inline] _cpu_down+0x523/0x1020 kernel/cpu.c:1457 cpu_down_maps_locked kernel/cpu.c:1483 [inline] cpu_down kernel/cpu.c:1491 [inline] cpu_device_down+0x82/0xc0 kernel/cpu.c:1508 device_offline drivers/base/core.c:4279 [inline] device_offline+0x2f4/0x400 drivers/base/core.c:4263 online_store+0xd1/0x180 drivers/base/core.c:2879 dev_attr_store+0x58/0x80 drivers/base/core.c:2505 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f01d579e0d9 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 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 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f01d4dfe028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f01d5a25fa0 RCX: 00007f01d579e0d9 RDX: 0000000000000002 RSI: 0000200000000180 RDI: 0000000000000003 RBP: 00007f01d5835024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f01d5a26038 R14: 00007f01d5a25fa0 R15: 00007ffe4c5cd718 Modules linked in: ---[ end trace 0000000000000000 ]--- RIP: 0010:__hlist_del include/linux/list.h:1029 [inline] RIP: 0010:detach_timer kernel/time/timer.c:891 [inline] RIP: 0010:migrate_timer_list kernel/time/timer.c:2493 [inline] RIP: 0010:timers_dead_cpu+0x326/0x860 kernel/time/timer.c:2541 Code: 0f 85 0c 04 00 00 48 8d 7b 08 48 8b 2b 48 89 f8 48 c1 e8 03 42 80 3c 38 00 0f 85 df 03 00 00 48 8b 43 08 48 89 c2 48 c1 ea 03 <42> 80 3c 3a 00 0f 85 b4 03 00 00 48 89 28 48 89 04 24 48 85 ed 74 RSP: 0018:ffffc900040078c0 EFLAGS: 00010046 RAX: 0000000000000000 RBX: ffff88806a523440 RCX: ffffffff81f5d5d8 RDX: 0000000000000000 RSI: ffffffff81f5d420 RDI: ffff88806a523448 RBP: dead000000000122 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffff88806a5258d0 R13: ffffed100d4a4b1a R14: ffff88806a6251c0 R15: dffffc0000000000 FS: 00007f01d4dfe6c0(0000) GS:ffff8880d5fec000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9c1ca70000 CR3: 000000003de42000 CR4: 0000000000352ef0 ---------------- Code disassembly (best guess): 0: 0f 85 0c 04 00 00 jne 0x412 6: 48 8d 7b 08 lea 0x8(%rbx),%rdi a: 48 8b 2b mov (%rbx),%rbp d: 48 89 f8 mov %rdi,%rax 10: 48 c1 e8 03 shr $0x3,%rax 14: 42 80 3c 38 00 cmpb $0x0,(%rax,%r15,1) 19: 0f 85 df 03 00 00 jne 0x3fe 1f: 48 8b 43 08 mov 0x8(%rbx),%rax 23: 48 89 c2 mov %rax,%rdx 26: 48 c1 ea 03 shr $0x3,%rdx * 2a: 42 80 3c 3a 00 cmpb $0x0,(%rdx,%r15,1) <-- trapping instruction 2f: 0f 85 b4 03 00 00 jne 0x3e9 35: 48 89 28 mov %rbp,(%rax) 38: 48 89 04 24 mov %rax,(%rsp) 3c: 48 85 ed test %rbp,%rbp 3f: 74 .byte 0x74 --- 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@googlegroups.com. 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 syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. 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