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Filename Latest commit message Latest commit date
Zheng Yejian 19b651db94 tracing/hist: Fix issue of losting command info in error_log
[ Upstream commit 608c6ed3337850c767ab0dd6c583477922233e29 ]

When input some constructed invalid 'trigger' command, command info
in 'error_log' are lost [1].

The root cause is that there is a path that event_hist_trigger_parse()
is recursely called once and 'last_cmd' which save origin command is
cleared, then later calling of hist_err() will no longer record origin
command info:

  event_hist_trigger_parse() {
    last_cmd_set()  // <1> 'last_cmd' save origin command here at first
    create_actions() {
      onmatch_create() {
        action_create() {
          trace_action_create() {
            trace_action_create_field_var() {
              create_field_var_hist() {
                event_hist_trigger_parse() {  // <2> recursely called once
                  hist_err_clear()  // <3> 'last_cmd' is cleared here
                }
                hist_err()  // <4> No longer find origin command!!!

Since 'glob' is empty string while running into the recurse call, we
can trickly check it and bypass the call of hist_err_clear() to solve it.

[1]
 # cd /sys/kernel/tracing
 # echo "my_synth_event int v1; int v2; int v3;" >> synthetic_events
 # echo 'hist:keys=pid' >> events/sched/sched_waking/trigger
 # echo "hist:keys=next_pid:onmatch(sched.sched_waking).my_synth_event(\
pid,pid1)" >> events/sched/sched_switch/trigger
 # cat error_log
[  8.405018] hist:sched:sched_switch: error: Couldn't find synthetic event
  Command:
hist:keys=next_pid:onmatch(sched.sched_waking).my_synth_event(pid,pid1)
                                                          ^
[  8.816902] hist:sched:sched_switch: error: Couldn't find field
  Command:
hist:keys=next_pid:onmatch(sched.sched_waking).my_synth_event(pid,pid1)
                          ^
[  8.816902] hist:sched:sched_switch: error: Couldn't parse field variable
  Command:
hist:keys=next_pid:onmatch(sched.sched_waking).my_synth_event(pid,pid1)
                          ^
[  8.999880] : error: Couldn't find field
  Command:
           ^
[  8.999880] : error: Couldn't parse field variable
  Command:
           ^
[  8.999880] : error: Couldn't find field
  Command:
           ^
[  8.999880] : error: Couldn't create histogram for field
  Command:
           ^

Link: https://lore.kernel.org/linux-trace-kernel/20221207135326.3483216-1-zhengyejian1@huawei.com

Cc: <mhiramat@kernel.org>
Cc: <zanussi@kernel.org>
Fixes: f404da6e1d ("tracing: Add 'last error' error facility for hist triggers")
Signed-off-by: Zheng Yejian <zhengyejian1@huawei.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-01-18 11:41:26 +01:00
arch MIPS: OCTEON: warn only once if deprecated link status is being used 2023-01-18 11:40:58 +01:00
block block: unhash blkdev part inode when the part is deleted 2022-12-19 12:24:16 +01:00
certs
crypto crypto: tcrypt - Fix multibuffer skcipher speed test mem leak 2023-01-18 11:41:19 +01:00
Documentation ASoC: dt-bindings: wcd9335: fix reset line polarity in example 2023-01-18 11:41:06 +01:00
drivers usb: storage: Add check for kcalloc 2023-01-18 11:41:26 +01:00
fs chardev: fix error handling in cdev_device_add() 2023-01-18 11:41:25 +01:00
include bonding: Rename slave_arr to usable_slaves 2023-01-18 11:41:05 +01:00
init init/Kconfig: fix CC_HAS_ASM_GOTO_TIED_OUTPUT test with dash 2022-12-08 11:22:59 +01:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel tracing/hist: Fix issue of losting command info in error_log 2023-01-18 11:41:26 +01:00
lib test_firmware: fix memory leak in test_firmware_init() 2023-01-18 11:41:23 +01:00
LICENSES
mm mm/hugetlb: fix races when looking up a CONT-PTE/PMD size hugetlb page 2022-12-19 12:24:15 +01:00
net Bluetooth: RFCOMM: don't call kfree_skb() under spin_lock_irqsave() 2023-01-18 11:41:16 +01:00
samples
scripts scripts/faddr2line: Fix regression in name resolution on ppc64le 2022-12-08 11:23:02 +01:00
security apparmor: Use pointer to struct aa_label for lbs_cred 2023-01-18 11:41:17 +01:00
sound ALSA: mts64: fix possible null-ptr-defer in snd_mts64_interrupt 2023-01-18 11:41:09 +01:00
tools netfilter: conntrack: set icmpv6 redirects as RELATED 2023-01-18 11:41:08 +01:00
usr
virt KVM: arm64: vgic: Fix exit condition in scan_its_table() 2022-10-29 10:20:35 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: add Chandan as xfs maintainer for 5.4.y 2022-09-28 11:03:58 +02:00
Makefile Linux 5.4.228 2022-12-19 12:24:17 +01:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.