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We've suffered from severe kernel crashes due to memory corruption on our production environment, like, Call Trace: [1640542.554277] general protection fault: 0000 [#1] SMP PTI [1640542.554856] CPU: 17 PID: 26996 Comm: python Kdump: loaded Tainted:G [1640542.556629] RIP: 0010:kmem_cache_alloc+0x90/0x190 [1640542.559074] RSP: 0018:ffffb16faa597df8 EFLAGS: 00010286 [1640542.559587] RAX: 0000000000000000 RBX: 0000000000400200 RCX: 0000000006e931bf [1640542.560323] RDX: 0000000006e931be RSI: 0000000000400200 RDI: ffff9a45ff004300 [1640542.560996] RBP: 0000000000400200 R08: 0000000000023420 R09: 0000000000000000 [1640542.561670] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff9a20608d [1640542.562366] R13: ffff9a45ff004300 R14: ffff9a45ff004300 R15: 696c662f65636976 [1640542.563128] FS: 00007f45d7c6f740(0000) GS:ffff9a45ff840000(0000) knlGS:0000000000000000 [1640542.563937] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [1640542.564557] CR2: 00007f45d71311a0 CR3: 000000189d63e004 CR4: 00000000003606e0 [1640542.565279] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [1640542.566069] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [1640542.566742] Call Trace: [1640542.567009] anon_vma_clone+0x5d/0x170 [1640542.567417] __split_vma+0x91/0x1a0 [1640542.567777] do_munmap+0x2c6/0x320 [1640542.568128] vm_munmap+0x54/0x70 [1640542.569990] __x64_sys_munmap+0x22/0x30 [1640542.572005] do_syscall_64+0x5b/0x1b0 [1640542.573724] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [1640542.575642] RIP: 0033:0x7f45d6e61e27 James Wang has reproduced it stably on the latest 4.19 LTS. After some debugging, we finally proved that it's due to ftrace buffer out-of-bound access using a debug tool as follows: [ 86.775200] BUG: Out-of-bounds write at addr 0xffff88aefe8b7000 [ 86.780806] no_context+0xdf/0x3c0 [ 86.784327] __do_page_fault+0x252/0x470 [ 86.788367] do_page_fault+0x32/0x140 [ 86.792145] page_fault+0x1e/0x30 [ 86.795576] strncpy_from_unsafe+0x66/0xb0 [ 86.799789] fetch_memory_string+0x25/0x40 [ 86.804002] fetch_deref_string+0x51/0x60 [ 86.808134] kprobe_trace_func+0x32d/0x3a0 [ 86.812347] kprobe_dispatcher+0x45/0x50 [ 86.816385] kprobe_ftrace_handler+0x90/0xf0 [ 86.820779] ftrace_ops_assist_func+0xa1/0x140 [ 86.825340] 0xffffffffc00750bf [ 86.828603] do_sys_open+0x5/0x1f0 [ 86.832124] do_syscall_64+0x5b/0x1b0 [ 86.835900] entry_SYSCALL_64_after_hwframe+0x44/0xa9 commit |
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.. | ||
blktrace.c | ||
bpf_trace.c | ||
bpf_trace.h | ||
error_report-traces.c | ||
fgraph.c | ||
ftrace_internal.h | ||
ftrace.c | ||
Kconfig | ||
kprobe_event_gen_test.c | ||
Makefile | ||
power-traces.c | ||
preemptirq_delay_test.c | ||
ring_buffer_benchmark.c | ||
ring_buffer.c | ||
rpm-traces.c | ||
synth_event_gen_test.c | ||
trace_benchmark.c | ||
trace_benchmark.h | ||
trace_boot.c | ||
trace_branch.c | ||
trace_clock.c | ||
trace_dynevent.c | ||
trace_dynevent.h | ||
trace_entries.h | ||
trace_event_perf.c | ||
trace_events_filter_test.h | ||
trace_events_filter.c | ||
trace_events_hist.c | ||
trace_events_inject.c | ||
trace_events_synth.c | ||
trace_events_trigger.c | ||
trace_events.c | ||
trace_export.c | ||
trace_functions_graph.c | ||
trace_functions.c | ||
trace_hwlat.c | ||
trace_irqsoff.c | ||
trace_kdb.c | ||
trace_kprobe_selftest.c | ||
trace_kprobe_selftest.h | ||
trace_kprobe.c | ||
trace_mmiotrace.c | ||
trace_nop.c | ||
trace_output.c | ||
trace_output.h | ||
trace_preemptirq.c | ||
trace_printk.c | ||
trace_probe_tmpl.h | ||
trace_probe.c | ||
trace_probe.h | ||
trace_recursion_record.c | ||
trace_sched_switch.c | ||
trace_sched_wakeup.c | ||
trace_selftest_dynamic.c | ||
trace_selftest.c | ||
trace_seq.c | ||
trace_stack.c | ||
trace_stat.c | ||
trace_stat.h | ||
trace_synth.h | ||
trace_syscalls.c | ||
trace_uprobe.c | ||
trace.c | ||
trace.h | ||
tracing_map.c | ||
tracing_map.h |