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linux/kernel/trace
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Chen Jun 9985d29c47 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 10:30:16 +01:00
..
blktrace.c blktrace: Fix uaf in blk_trace access after removing by sysfs 2021-09-24 11:06:15 -06:00
bpf_trace.c bpf: Forbid bpf_ktime_get_coarse_ns and bpf_timer_* in tracing progs 2021-11-25 09:49:07 +01:00
bpf_trace.h
error_report-traces.c
fgraph.c
ftrace_internal.h
ftrace.c tracing: Disable "other" permission bits in the tracefs files 2021-11-18 19:16:15 +01:00
Kconfig tracing: Simplify the Kconfig dependency of FTRACE 2021-08-16 11:37:20 -04:00
kprobe_event_gen_test.c
Makefile tracing: Add a probe that attaches to trace events 2021-08-20 14:18:40 -04:00
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 19:16:03 +01:00
rpm-traces.c
synth_event_gen_test.c
trace_benchmark.c
trace_benchmark.h
trace_boot.c tracing: Fix missing trace_boot_init_histograms kstrdup NULL checks 2021-11-18 19:16:41 +01:00
trace_branch.c
trace_clock.c
trace_dynevent.c tracing: Disable "other" permission bits in the tracefs files 2021-11-18 19:16:15 +01:00
trace_dynevent.h tracing: Add DYNAMIC flag for dynamic events 2021-08-18 18:10:32 -04:00
trace_entries.h
trace_eprobe.c tracing: Fix misspelling of "missing" 2021-10-29 09:54:14 -04:00
trace_event_perf.c ftrace: do CPU checking after preemption disabled 2021-11-18 19:16:20 +01:00
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 09:04:44 +01:00
trace_events_inject.c
trace_events_synth.c tracing: Disable "other" permission bits in the tracefs files 2021-11-18 19:16:15 +01:00
trace_events_trigger.c tracing: Add a probe that attaches to trace events 2021-08-20 14:18:40 -04:00
trace_events.c tracing: Check pid filtering when creating events 2021-12-01 09:04:55 +01:00
trace_export.c
trace_functions_graph.c tracing: Disable "other" permission bits in the tracefs files 2021-11-18 19:16:15 +01:00
trace_functions.c
trace_hwlat.c tracing: Disable "other" permission bits in the tracefs files 2021-11-18 19:16:15 +01:00
trace_irqsoff.c
trace_kdb.c kdb: Rename members of struct kdbtab_t 2021-07-27 17:05:06 +01:00
trace_kprobe_selftest.c
trace_kprobe_selftest.h
trace_kprobe.c tracing: Disable "other" permission bits in the tracefs files 2021-11-18 19:16:15 +01:00
trace_mmiotrace.c
trace_nop.c
trace_osnoise.c tracing: Disable "other" permission bits in the tracefs files 2021-11-18 19:16:15 +01:00
trace_output.c tracing: Add migrate-disabled counter to tracing output. 2021-09-03 19:42:35 -04:00
trace_output.h
trace_preemptirq.c
trace_printk.c tracing: Disable "other" permission bits in the tracefs files 2021-11-18 19:16:15 +01:00
trace_probe_tmpl.h tracing/probes: Have process_fetch_insn() take a void * instead of pt_regs 2021-08-19 09:09:03 -04:00
trace_probe.c tracing: Add a probe that attaches to trace events 2021-08-20 14:18:40 -04:00
trace_probe.h tracing: Add a probe that attaches to trace events 2021-08-20 14:18:40 -04:00
trace_recursion_record.c tracing: Disable "other" permission bits in the tracefs files 2021-11-18 19:16:15 +01:00
trace_sched_switch.c
trace_sched_wakeup.c tracing: Change variable type as bool for clean-up 2021-06-30 09:19:14 -04:00
trace_selftest_dynamic.c
trace_selftest.c
trace_seq.c
trace_stack.c tracing: Disable "other" permission bits in the tracefs files 2021-11-18 19:16:15 +01:00
trace_stat.c tracing: Disable "other" permission bits in the tracefs files 2021-11-18 19:16:15 +01:00
trace_stat.h
trace_synth.h tracing: synth events: increase max fields count 2021-09-08 15:29:16 -04:00
trace_syscalls.c
trace_uprobe.c tracing/uprobe: Fix uprobe_perf_open probes iteration 2021-12-01 09:04:43 +01:00
trace.c tracing: Don't use out-of-sync va_list in event printing 2021-12-08 09:04:41 +01:00
trace.h tracing: Fix pid filtering when triggers are attached 2021-12-01 09:04:43 +01:00
tracing_map.c tracing: Fix a kmemleak false positive in tracing_map 2021-12-17 10:30:16 +01:00
tracing_map.h