On Mon, May 04, 2020 at 03:11:09PM -0400, Qian Cai wrote: > Running a syscall fuzzer inside a container on linux-next floods systems with soft lockups. It looks like stuck in this line at iov_iter_copy_from_user_atomic(), Thoughts? > > iterate_all_kinds(i, bytes, v, > copyin((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len), > memcpy_from_page((p += v.bv_len) - v.bv_len, v.bv_page, > v.bv_offset, v.bv_len), > memcpy((p += v.iov_len) - v.iov_len, v.iov_base, v.iov_len) > ) If the size being copied is large enough, something like this might happen. Is this a CONFIG_PREEMPT=n kernel? And is the size passed in to iov_iter_copy_from_user_atomic() quite large, given that this is generated by a fuzzer? If so, one thing to try is to add cond_resched() in the iterate_bvec(), iterate_kvec(), and iterate_iovec() macros. Thanx, Paul > [18310.203791][ C118] watchdog: BUG: soft lockup - CPU#118 stuck for 22s! [trinity-c93:129976] > [18310.212289][ C118] Modules linked in: nfnetlink cn brd ext4 crc16 mbcache jbd2 loop nls_iso8859_1 nls_cp437 vfat fat kvm_amd kvm ses enclosure dax_pmem irqbypass dax_pmem_core efivars acpi_cpufreq efivarfs ip_tables x_tables xfs sd_mod smartpqi scsi_transport_sas mlx5_core tg3 libphy firmware_class dm_mirror dm_region_hash dm_log dm_mod [last unloaded: binfmt_misc] > [18310.245012][ C118] irq event stamp: 0 > [18310.248847][ C118] hardirqs last enabled at (0): [<0000000000000000>] 0x0 > [18310.255867][ C118] hardirqs last disabled at (0): [<ffffffffa5ebffef>] copy_process+0x10ff/0x30a0 > [18310.264889][ C118] softirqs last enabled at (0): [<ffffffffa5ebffef>] copy_process+0x10ff/0x30a0 > [18310.273908][ C118] softirqs last disabled at (0): [<0000000000000000>] 0x0 > [18310.280958][ C118] CPU: 118 PID: 129976 Comm: trinity-c93 Tainted: G O L 5.7.0-rc4-next-20200504+ #1 > [18310.291463][ C118] Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 > [18310.300814][ C118] RIP: 0010:iov_iter_copy_from_user_atomic+0x3b4/0x510 > lib/iov_iter.c:1000 (discriminator 10) > [18310.307699][ C118] Code: 92 dd ff 41 8b 47 08 8b 75 c8 8b 55 b8 29 d8 81 e2 ff 0f 00 00 39 f0 0f 47 c6 89 c1 b8 00 10 00 00 29 d0 39 c1 0f 46 c1 85 c0 <74> 55 4c 89 ff 89 45 d0 89 55 a4 e8 2c 93 dd ff 8b 75 b8 48 8b 7d > [18310.327430][ C118] RSP: 0018:ffffc900387f7758 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 > [18310.335863][ C118] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000 > [18310.343747][ C118] RDX: 0000000000000000 RSI: 0000000000000b99 RDI: ffff888c8f804208 > [18310.351731][ C118] RBP: ffffc900387f77b8 R08: ffffed1117c50075 R09: ffffed1117c50075 > [18310.359659][ C118] R10: ffff8888be2803a7 R11: ffffed1117c50074 R12: 0000000000000b99 > [18310.367624][ C118] R13: ffffc900387f7c30 R14: 0000000000000000 R15: ffff888c8f804200 > [18310.375601][ C118] FS: 00007f733446f740(0000) GS:ffff889030700000(0000) knlGS:0000000000000000 > [18310.384444][ C118] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [18310.391026][ C118] CR2: 00007f73340852fc CR3: 00000009e6ea4000 CR4: 00000000003406e0 > [18310.398951][ C118] Call Trace: > [18310.402123][ C118] generic_perform_write+0x254/0x340 > [18310.407402][ C118] ? filemap_check_errors+0xb0/0xb0 > [18310.412493][ C118] ? file_update_time+0x18a/0x220 > [18310.417532][ C118] ? update_time+0x70/0x70 > [18310.421836][ C118] ? __kasan_check_write+0x14/0x20 > [18310.426928][ C118] __generic_file_write_iter+0x1a5/0x2a0 > [18310.432453][ C118] generic_file_write_iter+0x219/0x2d8 > [18310.437900][ C118] ? kernel_text_address+0x59/0xc0 > [18310.442901][ C118] ? __generic_file_write_iter+0x2a0/0x2a0 > [18310.448670][ C118] do_iter_readv_writev+0x2cb/0x3d0 > [18310.453757][ C118] ? default_llseek+0x140/0x140 > [18310.458571][ C118] ? create_object+0x4a7/0x540 > [18310.463224][ C118] do_iter_write+0xd7/0x2b0 > [18310.467680][ C118] vfs_iter_write+0x4e/0x70 > [18310.472072][ C118] iter_file_splice_write+0x44a/0x620 > [18310.477430][ C118] ? page_cache_pipe_buf_steal+0x130/0x130 > [18310.483130][ C118] ? debug_lockdep_rcu_enabled+0x27/0x60 > [18310.488709][ C118] ? ___might_sleep+0x178/0x210 > [18310.493449][ C118] ? __sb_start_write+0x17b/0x270 > [18310.498476][ C118] do_splice+0x5ce/0xa20 > [18310.502602][ C118] ? __task_pid_nr_ns+0x5/0x290 > [18310.507426][ C118] ? __task_pid_nr_ns+0x145/0x290 > [18310.512339][ C118] ? default_file_splice_write+0x40/0x40 > [18310.517952][ C118] ? __kasan_check_read+0x11/0x20 > [18310.522866][ C118] ? __fget_light+0xba/0x120 > [18310.527423][ C118] __x64_sys_splice+0x16e/0x180 > [18310.532163][ C118] do_syscall_64+0xcc/0xaf0 > [18310.536643][ C118] ? syscall_return_slowpath+0x580/0x580 > [18310.542168][ C118] ? lockdep_hardirqs_off+0x1f/0x140 > [18310.547386][ C118] ? entry_SYSCALL_64_after_hwframe+0x3e/0xb3 > [18310.553349][ C118] ? trace_hardirqs_off_caller+0x3a/0x150 > [18310.559046][ C118] ? trace_hardirqs_off_thunk+0x1a/0x1c > [18310.564484][ C118] entry_SYSCALL_64_after_hwframe+0x49/0xb3 > [18310.570342][ C118] RIP: 0033:0x7f73345b070d > [18310.574647][ C118] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 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 8b 0d 53 f7 0c 00 f7 d8 64 89 01 48 > [18310.594352][ C118] RSP: 002b:00007ffe560d32f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 > [18310.602719][ C118] RAX: ffffffffffffffda RBX: 0000000000000113 RCX: 00007f73345b070d > [18310.610653][ C118] RDX: 00000000000000a0 RSI: 0000000000000000 RDI: 00000000000000b1 > [18310.618628][ C118] RBP: 0000000000000113 R08: 0000000000001000 R09: 0000000000000002 > [18310.626597][ C118] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002 > [18310.634477][ C118] R13: 00007f7332cd5058 R14: 00007f733446f6c0 R15: 00007f7332cd5000 > [18321.464794][ C118] rcu: INFO: rcu_sched self-detected stall on CPU > [18321.471149][ C118] rcu: 118-....: (6410 ticks this GP) idle=496/1/0x4000000000000002 softirq=311635/311638 fqs=2933 > [18321.482019][ C118] (t=6502 jiffies g=1028673 q=377159) > [18321.487375][ C118] NMI backtrace for cpu 118 > [18321.491767][ C118] CPU: 118 PID: 129976 Comm: trinity-c93 Tainted: G O L 5.7.0-rc4-next-20200504+ #1 > [18321.502180][ C118] Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019 > [18321.511477][ C118] Call Trace: > [18321.514643][ C118] <IRQ> > [18321.517381][ C118] dump_stack+0xa7/0xea > [18321.521423][ C118] nmi_cpu_backtrace.cold.9+0x2e/0x33 > [18321.526706][ C118] ? nmi_cpu_backtrace_handler+0x20/0x20 > [18321.532230][ C118] nmi_trigger_cpumask_backtrace+0x19f/0x1b2 > [18321.538108][ C118] arch_trigger_cpumask_backtrace+0x19/0x20 > [18321.543898][ C118] rcu_dump_cpu_stacks+0x1a3/0x1ee > [18321.549030][ C118] rcu_sched_clock_irq.cold.110+0xe9/0x73a > [18321.554731][ C118] ? trace_hardirqs_off+0x3a/0x150 > [18321.559858][ C118] update_process_times+0x28/0x60 > [18321.564776][ C118] tick_sched_handle+0x44/0x90 > [18321.569525][ C118] tick_sched_timer+0x3c/0xa0 > [18321.574086][ C118] __hrtimer_run_queues+0x45d/0x8c0 > [18321.579251][ C118] ? tick_sched_do_timer+0x90/0x90 > [18321.584249][ C118] ? enqueue_hrtimer+0x240/0x240 > [18321.589203][ C118] ? trace_hardirqs_off+0x3a/0x150 > [18321.594205][ C118] ? ktime_get_update_offsets_now+0xb7/0x1f0 > [18321.600167][ C118] hrtimer_interrupt+0x1aa/0x360 > [18321.605071][ C118] ? __kasan_check_read+0x11/0x20 > [18321.610023][ C118] smp_apic_timer_interrupt+0x103/0x430 > [18321.615518][ C118] apic_timer_interrupt+0xf/0x20 > [18321.620341][ C118] </IRQ> > [18321.623160][ C118] RIP: 0010:iov_iter_copy_from_user_atomic+0x35d/0x510 > [18321.629982][ C118] Code: fe ff ff 49 8d 45 18 44 89 65 c8 45 31 f6 48 89 45 a8 8b 45 c8 85 c0 0f 84 0e fe ff ff 48 8b 7d a8 e8 97 93 dd ff 49 8b 4d 18 <44> 89 f0 48 c1 e0 04 48 89 4d d0 48 01 c1 49 89 cf 48 8d 79 0c 48 > [18321.649567][ C118] RSP: 0018:ffffc900387f7758 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13 > [18321.657890][ C118] RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff888c8f804200 > [18321.665906][ C118] RDX: dffffc0000000000 RSI: 0000000000000b99 RDI: ffffc900387f7c48 > [18321.673789][ C118] RBP: ffffc900387f77b8 R08: ffffed1117c50075 R09: ffffed1117c50075 > [18321.681753][ C118] R10: ffff8888be2803a7 R11: ffffed1117c50074 R12: 0000000000000b99 > [18321.689635][ C118] R13: ffffc900387f7c30 R14: 0000000000000000 R15: ffff888c8f804200 > [18321.697523][ C118] ? iov_iter_copy_from_user_atomic+0x359/0x510 > [18321.703660][ C118] generic_perform_write+0x254/0x340 > [18321.708920][ C118] ? filemap_check_errors+0xb0/0xb0 > [18321.714010][ C118] ? file_update_time+0x18a/0x220 > [18321.718944][ C118] ? update_time+0x70/0x70 > [18321.723242][ C118] ? __kasan_check_write+0x14/0x20 > [18321.728310][ C118] __generic_file_write_iter+0x1a5/0x2a0 > [18321.733833][ C118] generic_file_write_iter+0x219/0x2d8 > [18321.739236][ C118] ? kernel_text_address+0x59/0xc0 > [18321.744237][ C118] ? __generic_file_write_iter+0x2a0/0x2a0 > [18321.749937][ C118] do_iter_readv_writev+0x2cb/0x3d0 > [18321.755095][ C118] ? default_llseek+0x140/0x140 > [18321.759834][ C118] ? create_object+0x4a7/0x540 > [18321.764488][ C118] do_iter_write+0xd7/0x2b0 > [18321.768878][ C118] vfs_iter_write+0x4e/0x70 > [18321.773273][ C118] iter_file_splice_write+0x44a/0x620 > [18321.778537][ C118] ? page_cache_pipe_buf_steal+0x130/0x130 > [18321.784237][ C118] ? debug_lockdep_rcu_enabled+0x27/0x60 > [18321.789760][ C118] ? ___might_sleep+0x178/0x210 > [18321.794500][ C118] ? __sb_start_write+0x17b/0x270 > [18321.799410][ C118] do_splice+0x5ce/0xa20 > [18321.803534][ C118] ? __task_pid_nr_ns+0x5/0x290 > [18321.808275][ C118] ? __task_pid_nr_ns+0x145/0x290 > [18321.813186][ C118] ? default_file_splice_write+0x40/0x40 > [18321.818709][ C118] ? __kasan_check_read+0x11/0x20 > [18321.823622][ C118] ? __fget_light+0xba/0x120 > [18321.828131][ C118] __x64_sys_splice+0x16e/0x180 > [18321.832868][ C118] do_syscall_64+0xcc/0xaf0 > [18321.837290][ C118] ? syscall_return_slowpath+0x580/0x580 > [18321.842817][ C118] ? lockdep_hardirqs_off+0x1f/0x140 > [18321.847991][ C118] ? entry_SYSCALL_64_after_hwframe+0x3e/0xb3 > [18321.853952][ C118] ? trace_hardirqs_off_caller+0x3a/0x150 > [18321.859565][ C118] ? trace_hardirqs_off_thunk+0x1a/0x1c > [18321.865040][ C118] entry_SYSCALL_64_after_hwframe+0x49/0xb3 > [18321.870867][ C118] RIP: 0033:0x7f73345b070d > [18321.875174][ C118] Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 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 8b 0d 53 f7 0c 00 f7 d8 64 89 01 48 > [18321.894764][ C118] RSP: 002b:00007ffe560d32f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000113 > [18321.903082][ C118] RAX: ffffffffffffffda RBX: 0000000000000113 RCX: 00007f73345b070d > [18321.910963][ C118] RDX: 00000000000000a0 RSI: 0000000000000000 RDI: 00000000000000b1 > [18321.918845][ C118] RBP: 0000000000000113 R08: 0000000000001000 R09: 0000000000000002 > [18321.926724][ C118] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000002 > [18321.934605][ C118] R13: 00007f7332cd5058 R14: 00007f733446f6c0 R15: 00007f7332cd5000 > INFO: task trinity-c93:129976 can't die for more than 1725 seconds. > [20088.049356][ T794] trinity-c93 R running task 27728 129976 97040 0x8000000e > [20088.057298][ T794] Call Trace: > [20088.060541][ T794] ? __kasan_check_read+0x11/0x20 > [20088.065459][ T794] ? activate_page+0x233/0x330 > [20088.070157][ T794] ? __kasan_check_read+0x11/0x20 > [20088.075074][ T794] ? mark_page_accessed+0x10a/0x5f0 > [20088.080202][ T794] ? retint_kernel+0x10/0x10 > [20088.084681][ T794] ? lockdep_hardirqs_on+0x16/0x2c0 > [20088.089772][ T794] ? retint_kernel+0x10/0x10 > [20088.094288][ T794] ? trace_hardirqs_on_caller+0x3a/0x160 > [20088.099909][ T794] ? trace_hardirqs_on_thunk+0x1a/0x1c > [20088.105306][ T794] ? irq_exit+0x60/0xf0 > [20088.109346][ T794] ? retint_kernel+0x10/0x10 > [20088.113857][ T794] ? iov_iter_copy_from_user_atomic+0x359/0x510 > [20088.120156][ T794] ? __asan_load8+0x30/0xb0 > [20088.124602][ T794] ? iov_iter_copy_from_user_atomic+0x38d/0x510 > [20088.130850][ T794] ? generic_perform_write+0x254/0x340 > [20088.136204][ T794] ? filemap_check_errors+0xb0/0xb0 > [20088.141384][ T794] ? file_update_time+0x18a/0x220 > [20088.146299][ T794] ? update_time+0x70/0x70 > [20088.150633][ T794] ? __kasan_check_write+0x14/0x20 > [20088.155637][ T794] ? __generic_file_write_iter+0x1a5/0x2a0 > [20088.161371][ T794] ? generic_file_write_iter+0x219/0x2d8 > [20088.166902][ T794] ? kernel_text_address+0x59/0xc0 > [20088.171936][ T794] ? __generic_file_write_iter+0x2a0/0x2a0 > [20088.177638][ T794] ? do_iter_readv_writev+0x2cb/0x3d0 > [20088.182931][ T794] ? default_llseek+0x140/0x140 > [20088.187672][ T794] ? create_object+0x4a7/0x540 > [20088.192350][ T794] ? do_iter_write+0xd7/0x2b0 > [20088.196919][ T794] ? vfs_iter_write+0x4e/0x70 > [20088.201512][ T794] ? iter_file_splice_write+0x44a/0x620 > [20088.206952][ T794] ? page_cache_pipe_buf_steal+0x130/0x130 > [20088.212686][ T794] ? debug_lockdep_rcu_enabled+0x27/0x60 > [20088.218213][ T794] ? ___might_sleep+0x178/0x210 > [20088.223046][ T794] ? __sb_start_write+0x17b/0x270 > [20088.227959][ T794] ? do_splice+0x5ce/0xa20 > [20088.232290][ T794] ? __task_pid_nr_ns+0x5/0x290 > [20088.237028][ T794] ? __task_pid_nr_ns+0x145/0x290 > [20088.242054][ T794] ? default_file_splice_write+0x40/0x40 > [20088.247579][ T794] ? __kasan_check_read+0x11/0x20 > [20088.252564][ T794] ? __fget_light+0xba/0x120 > [20088.257041][ T794] ? __x64_sys_splice+0x16e/0x180 > [20088.262010][ T794] ? do_syscall_64+0xcc/0xaf0 > [20088.266575][ T794] ? syscall_return_slowpath+0x580/0x580 > [20088.272144][ T794] ? lockdep_hardirqs_off+0x1f/0x140 > [20088.277320][ T794] ? entry_SYSCALL_64_after_hwframe+0x3e/0xb3 > [20088.283305][ T794] ? trace_hardirqs_off_caller+0x3a/0x150 > [20088.288920][ T794] ? trace_hardirqs_off_thunk+0x1a/0x1c > [20088.294398][ T794] ? entry_SYSCALL_64_after_hwframe+0x49/0xb3
