linux/kernel/trace
Chen Jun 6f0d9d3e74 tracing: Fix a kmemleak false positive in tracing_map
[ Upstream commit f25667e598 ]

Doing the command:
  echo 'hist:key=common_pid.execname,common_timestamp' > /sys/kernel/debug/tracing/events/xxx/trigger

Triggers many kmemleak reports:

unreferenced object 0xffff0000c7ea4980 (size 128):
  comm "bash", pid 338, jiffies 4294912626 (age 9339.324s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000f3469921>] kmem_cache_alloc_trace+0x4c0/0x6f0
    [<0000000054ca40c3>] hist_trigger_elt_data_alloc+0x140/0x178
    [<00000000633bd154>] tracing_map_init+0x1f8/0x268
    [<000000007e814ab9>] event_hist_trigger_func+0xca0/0x1ad0
    [<00000000bf8520ed>] trigger_process_regex+0xd4/0x128
    [<00000000f549355a>] event_trigger_write+0x7c/0x120
    [<00000000b80f898d>] vfs_write+0xc4/0x380
    [<00000000823e1055>] ksys_write+0x74/0xf8
    [<000000008a9374aa>] __arm64_sys_write+0x24/0x30
    [<0000000087124017>] do_el0_svc+0x88/0x1c0
    [<00000000efd0dcd1>] el0_svc+0x1c/0x28
    [<00000000dbfba9b3>] el0_sync_handler+0x88/0xc0
    [<00000000e7399680>] el0_sync+0x148/0x180
unreferenced object 0xffff0000c7ea4980 (size 128):
  comm "bash", pid 338, jiffies 4294912626 (age 9339.324s)
  hex dump (first 32 bytes):
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
    00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
  backtrace:
    [<00000000f3469921>] kmem_cache_alloc_trace+0x4c0/0x6f0
    [<0000000054ca40c3>] hist_trigger_elt_data_alloc+0x140/0x178
    [<00000000633bd154>] tracing_map_init+0x1f8/0x268
    [<000000007e814ab9>] event_hist_trigger_func+0xca0/0x1ad0
    [<00000000bf8520ed>] trigger_process_regex+0xd4/0x128
    [<00000000f549355a>] event_trigger_write+0x7c/0x120
    [<00000000b80f898d>] vfs_write+0xc4/0x380
    [<00000000823e1055>] ksys_write+0x74/0xf8
    [<000000008a9374aa>] __arm64_sys_write+0x24/0x30
    [<0000000087124017>] do_el0_svc+0x88/0x1c0
    [<00000000efd0dcd1>] el0_svc+0x1c/0x28
    [<00000000dbfba9b3>] el0_sync_handler+0x88/0xc0
    [<00000000e7399680>] el0_sync+0x148/0x180

The reason is elts->pages[i] is alloced by get_zeroed_page.
and kmemleak will not scan the area alloced by get_zeroed_page.
The address stored in elts->pages will be regarded as leaked.

That is, the elts->pages[i] will have pointers loaded onto it as well, and
without telling kmemleak about it, those pointers will look like memory
without a reference.

To fix this, call kmemleak_alloc to tell kmemleak to scan elts->pages[i]

Link: https://lkml.kernel.org/r/20211124140801.87121-1-chenjun102@huawei.com

Signed-off-by: Chen Jun <chenjun102@huawei.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-12-17 10:14:40 +01:00
..
blktrace.c blktrace: Fix uaf in blk_trace access after removing by sysfs 2021-09-30 10:11:05 +02:00
bpf_trace.c bpf: Add lockdown check for probe_write_user helper 2021-08-15 14:00:25 +02:00
bpf_trace.h
fgraph.c fgraph: Initialize tracing_graph_pause at task creation 2021-02-10 09:29:16 +01:00
ftrace_internal.h
ftrace.c tracing: Have all levels of checks prevent recursion 2021-10-27 09:56:56 +02:00
Kconfig tracing/kprobes: Do the notrace functions check without kprobes on ftrace 2021-01-19 18:27:19 +01:00
kprobe_event_gen_test.c
Makefile
power-traces.c
preemptirq_delay_test.c
ring_buffer_benchmark.c
ring_buffer.c ring-buffer: Protect ring_buffer_reset() from reentrancy 2021-11-18 14:03:49 +01:00
rpm-traces.c
synth_event_gen_test.c tracing: Add support for dynamic strings to synthetic events 2020-10-05 19:32:18 -04:00
trace_benchmark.c
trace_benchmark.h
trace_boot.c tracing/boot: Fix a hist trigger dependency for boot time tracing 2021-09-22 12:28:03 +02:00
trace_branch.c
trace_clock.c tracing: Do no increment trace_clock_global() by one 2021-06-23 14:42:50 +02:00
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 tracing/histograms: String compares should not care about signed values 2021-12-08 09:03:22 +01:00
trace_events_inject.c
trace_events_synth.c tracing: Make -ENOMEM the default error for parse_synth_field() 2020-11-02 15:58:32 -05:00
trace_events_trigger.c
trace_events.c tracing: Check pid filtering when creating events 2021-12-01 09:19:09 +01:00
trace_export.c treewide: Convert macro and uses of __section(foo) to __section("foo") 2020-10-25 14:51:49 -07:00
trace_functions_graph.c
trace_functions.c tracing: Have all levels of checks prevent recursion 2021-10-27 09:56:56 +02:00
trace_hwlat.c tracing: Remove WARN_ON in start_thread() 2020-11-30 21:43:07 -05:00
trace_irqsoff.c tracing: Use pause-on-trace with the latency tracers 2021-02-10 09:29:16 +01:00
trace_kdb.c
trace_kprobe_selftest.c
trace_kprobe_selftest.h
trace_kprobe.c tracing/probes: Reject events which have the same name of existing one 2021-09-22 12:28:00 +02:00
trace_mmiotrace.c
trace_nop.c
trace_output.c
trace_output.h
trace_preemptirq.c
trace_printk.c Updates for tracing and bootconfig: 2020-10-15 15:51:28 -07:00
trace_probe_tmpl.h
trace_probe.c tracing/probes: Reject events which have the same name of existing one 2021-09-22 12:28:00 +02:00
trace_probe.h tracing/probes: Reject events which have the same name of existing one 2021-09-22 12:28:00 +02:00
trace_sched_switch.c
trace_sched_wakeup.c
trace_selftest_dynamic.c
trace_selftest.c tracing: Disable ftrace selftests when any tracer is running 2020-12-30 11:54:28 +01:00
trace_seq.c
trace_stack.c
trace_stat.c
trace_stat.h
trace_synth.h tracing: Synthetic event field_pos is an index not a boolean 2021-07-28 14:35:45 +02:00
trace_syscalls.c
trace_uprobe.c tracing/uprobe: Fix uprobe_perf_open probes iteration 2021-12-01 09:19:01 +01:00
trace.c tracing: Fix NULL pointer dereference in start_creating 2021-08-12 13:22:12 +02:00
trace.h tracing: Fix pid filtering when triggers are attached 2021-12-01 09:19:01 +01:00
tracing_map.c tracing: Fix a kmemleak false positive in tracing_map 2021-12-17 10:14:40 +01:00
tracing_map.h