Hello, syzbot found the following issue on: HEAD commit: be548645527a Merge tag 'for-linus' of git://git.kernel.org.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=11fbb1df980000 kernel config: https://syzkaller.appspot.com/x/.config?x=ad08f7f48e13abcd dashboard link: https://syzkaller.appspot.com/bug?extid=674b1c12641a6992f1d5 compiler: gcc (Debian 12.2.0-14) 12.2.0, 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/68edb33a6611/disk-be548645.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/9c748ff58068/vmlinux-be548645.xz kernel image: https://storage.googleapis.com/syzbot-assets/6ae2859fc0e3/bzImage-be548645.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+674b1c12641a6992f1d5@xxxxxxxxxxxxxxxxxxxxxxxxx ====================================================== WARNING: possible circular locking dependency detected 6.13.0-rc6-syzkaller-00290-gbe548645527a #0 Not tainted ------------------------------------------------------ syz.7.2798/18466 is trying to acquire lock: ffff8880621f6988 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: inode_lock include/linux/fs.h:818 [inline] ffff8880621f6988 (&sb->s_type->i_mutex_key#3){++++}-{4:4}, at: start_creating.part.0+0xb0/0x3a0 fs/debugfs/inode.c:374 but task is already holding lock: ffffffff8de395c8 (relay_channels_mutex){+.+.}-{4:4}, at: relay_open+0x324/0xa20 kernel/relay.c:515 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (relay_channels_mutex){+.+.}-{4:4}: __mutex_lock_common kernel/locking/mutex.c:585 [inline] __mutex_lock+0x19b/0xa60 kernel/locking/mutex.c:735 relay_prepare_cpu+0x2c/0x300 kernel/relay.c:438 cpuhp_invoke_callback+0x3d0/0xa10 kernel/cpu.c:194 __cpuhp_invoke_callback_range+0x101/0x200 kernel/cpu.c:965 cpuhp_invoke_callback_range kernel/cpu.c:989 [inline] cpuhp_up_callbacks kernel/cpu.c:1020 [inline] _cpu_up+0x3fd/0x910 kernel/cpu.c:1690 cpu_up+0x1dc/0x240 kernel/cpu.c:1722 cpuhp_bringup_mask+0xdc/0x210 kernel/cpu.c:1788 cpuhp_bringup_cpus_parallel kernel/cpu.c:1878 [inline] bringup_nonboot_cpus+0x176/0x1c0 kernel/cpu.c:1892 smp_init+0x34/0x160 kernel/smp.c:1009 kernel_init_freeable+0x3ad/0x8b0 init/main.c:1569 kernel_init+0x1c/0x2b0 init/main.c:1466 ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 -> #1 (cpu_hotplug_lock){++++}-{0:0}: percpu_down_read include/linux/percpu-rwsem.h:51 [inline] cpus_read_lock+0x42/0x160 kernel/cpu.c:490 acomp_ctx_get_cpu mm/zswap.c:886 [inline] zswap_compress mm/zswap.c:908 [inline] zswap_store_page mm/zswap.c:1439 [inline] zswap_store+0x8f8/0x25f0 mm/zswap.c:1546 swap_writepage+0x3b6/0x1120 mm/page_io.c:279 shmem_writepage+0xf7b/0x1490 mm/shmem.c:1579 pageout+0x3b2/0xaa0 mm/vmscan.c:696 shrink_folio_list+0x3025/0x42d0 mm/vmscan.c:1374 evict_folios+0x6e3/0x19c0 mm/vmscan.c:4600 try_to_shrink_lruvec+0x61e/0xa80 mm/vmscan.c:4796 lru_gen_shrink_lruvec mm/vmscan.c:4945 [inline] shrink_lruvec+0x313/0x2ba0 mm/vmscan.c:5700 shrink_node_memcgs mm/vmscan.c:5936 [inline] shrink_node mm/vmscan.c:5977 [inline] shrink_node+0x105e/0x3f20 mm/vmscan.c:5955 shrink_zones mm/vmscan.c:6222 [inline] do_try_to_free_pages+0x35f/0x1a30 mm/vmscan.c:6284 try_to_free_mem_cgroup_pages+0x31a/0x7a0 mm/vmscan.c:6616 try_charge_memcg+0x356/0xaf0 mm/memcontrol.c:2238 obj_cgroup_charge_pages mm/memcontrol.c:2646 [inline] obj_cgroup_charge+0x179/0x4d0 mm/memcontrol.c:2937 __memcg_slab_post_alloc_hook+0x1b6/0x9b0 mm/memcontrol.c:2998 memcg_slab_post_alloc_hook mm/slub.c:2152 [inline] slab_post_alloc_hook mm/slub.c:4129 [inline] slab_alloc_node mm/slub.c:4168 [inline] kmem_cache_alloc_lru_noprof+0x30d/0x3b0 mm/slub.c:4187 alloc_inode+0xbf/0x230 fs/inode.c:338 new_inode_pseudo fs/inode.c:1174 [inline] new_inode+0x22/0x210 fs/inode.c:1193 debugfs_get_inode fs/debugfs/inode.c:72 [inline] __debugfs_create_file+0x11a/0x660 fs/debugfs/inode.c:433 debugfs_create_file_full+0x6d/0xa0 fs/debugfs/inode.c:462 kvm_create_vm_debugfs virt/kvm/kvm_main.c:1056 [inline] kvm_create_vm virt/kvm/kvm_main.c:1193 [inline] kvm_dev_ioctl_create_vm virt/kvm/kvm_main.c:5353 [inline] kvm_dev_ioctl+0x16b7/0x1aa0 virt/kvm/kvm_main.c:5395 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f -> #0 (&sb->s_type->i_mutex_key#3){++++}-{4:4}: check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849 down_write+0x93/0x200 kernel/locking/rwsem.c:1577 inode_lock include/linux/fs.h:818 [inline] start_creating.part.0+0xb0/0x3a0 fs/debugfs/inode.c:374 start_creating fs/debugfs/inode.c:351 [inline] __debugfs_create_file+0xa5/0x660 fs/debugfs/inode.c:423 debugfs_create_file_full+0x6d/0xa0 fs/debugfs/inode.c:462 relay_create_buf_file+0xf0/0x170 kernel/relay.c:360 relay_open_buf.part.0+0x760/0xb90 kernel/relay.c:389 relay_open_buf kernel/relay.c:536 [inline] relay_open+0x5e2/0xa20 kernel/relay.c:517 do_blk_trace_setup+0x4b4/0xac0 kernel/trace/blktrace.c:590 __blk_trace_setup+0xd8/0x180 kernel/trace/blktrace.c:630 blk_trace_setup+0x47/0x70 kernel/trace/blktrace.c:648 sg_ioctl_common drivers/scsi/sg.c:1114 [inline] sg_ioctl+0x7a3/0x26b0 drivers/scsi/sg.c:1156 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f other info that might help us debug this: Chain exists of: &sb->s_type->i_mutex_key#3 --> cpu_hotplug_lock --> relay_channels_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(relay_channels_mutex); lock(cpu_hotplug_lock); lock(relay_channels_mutex); lock(&sb->s_type->i_mutex_key#3); *** DEADLOCK *** 2 locks held by syz.7.2798/18466: #0: ffff8881433b1ca8 (&q->debugfs_mutex){+.+.}-{4:4}, at: blk_trace_setup+0x33/0x70 kernel/trace/blktrace.c:647 #1: ffffffff8de395c8 (relay_channels_mutex){+.+.}-{4:4}, at: relay_open+0x324/0xa20 kernel/relay.c:515 stack backtrace: CPU: 1 UID: 0 PID: 18466 Comm: syz.7.2798 Not tainted 6.13.0-rc6-syzkaller-00290-gbe548645527a #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+0x116/0x1f0 lib/dump_stack.c:120 print_circular_bug+0x41c/0x610 kernel/locking/lockdep.c:2074 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2206 check_prev_add kernel/locking/lockdep.c:3161 [inline] check_prevs_add kernel/locking/lockdep.c:3280 [inline] validate_chain kernel/locking/lockdep.c:3904 [inline] __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5226 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5849 down_write+0x93/0x200 kernel/locking/rwsem.c:1577 inode_lock include/linux/fs.h:818 [inline] start_creating.part.0+0xb0/0x3a0 fs/debugfs/inode.c:374 start_creating fs/debugfs/inode.c:351 [inline] __debugfs_create_file+0xa5/0x660 fs/debugfs/inode.c:423 debugfs_create_file_full+0x6d/0xa0 fs/debugfs/inode.c:462 relay_create_buf_file+0xf0/0x170 kernel/relay.c:360 relay_open_buf.part.0+0x760/0xb90 kernel/relay.c:389 relay_open_buf kernel/relay.c:536 [inline] relay_open+0x5e2/0xa20 kernel/relay.c:517 do_blk_trace_setup+0x4b4/0xac0 kernel/trace/blktrace.c:590 __blk_trace_setup+0xd8/0x180 kernel/trace/blktrace.c:630 blk_trace_setup+0x47/0x70 kernel/trace/blktrace.c:648 sg_ioctl_common drivers/scsi/sg.c:1114 [inline] sg_ioctl+0x7a3/0x26b0 drivers/scsi/sg.c:1156 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:906 [inline] __se_sys_ioctl fs/ioctl.c:892 [inline] __x64_sys_ioctl+0x190/0x200 fs/ioctl.c:892 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f596cf85d29 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:00007f596de83038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f596d176080 RCX: 00007f596cf85d29 RDX: 0000000000000038 RSI: 00000000c0481273 RDI: 0000000000000003 RBP: 00007f596d001b08 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f596d176080 R15: 00007ffc52cefc58 </TASK> --- 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
