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Filename Latest commit message Latest commit date
Petr Pavlu 8244ea916b tracing: Fix a warning when allocating buffered events fails
[ Upstream commit 34209fe83ef8404353f91ab4ea4035dbc9922d04 ]

Function trace_buffered_event_disable() produces an unexpected warning
when the previous call to trace_buffered_event_enable() fails to
allocate pages for buffered events.

The situation can occur as follows:

* The counter trace_buffered_event_ref is at 0.

* The soft mode gets enabled for some event and
  trace_buffered_event_enable() is called. The function increments
  trace_buffered_event_ref to 1 and starts allocating event pages.

* The allocation fails for some page and trace_buffered_event_disable()
  is called for cleanup.

* Function trace_buffered_event_disable() decrements
  trace_buffered_event_ref back to 0, recognizes that it was the last
  use of buffered events and frees all allocated pages.

* The control goes back to trace_buffered_event_enable() which returns.
  The caller of trace_buffered_event_enable() has no information that
  the function actually failed.

* Some time later, the soft mode is disabled for the same event.
  Function trace_buffered_event_disable() is called. It warns on
  "WARN_ON_ONCE(!trace_buffered_event_ref)" and returns.

Buffered events are just an optimization and can handle failures. Make
trace_buffered_event_enable() exit on the first failure and left any
cleanup later to when trace_buffered_event_disable() is called.

Link: https://lore.kernel.org/all/20231127151248.7232-2-petr.pavlu@suse.com/
Link: https://lkml.kernel.org/r/20231205161736.19663-3-petr.pavlu@suse.com

Fixes: 0fc1b09ff1 ("tracing: Use temp buffer when filtering events")
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-12-13 18:18:13 +01:00
arch s390/cmma: fix detection of DAT pages 2023-12-08 08:44:27 +01:00
block block/partition: fix signedness issue for Amiga partitions 2023-07-27 08:37:29 +02:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:11:22 +02:00
crypto crypto: pcrypt - Fix hungtask for PADATA_RESET 2023-11-28 16:50:14 +00:00
Documentation firmware: ti_sci: Replace HTTP links with HTTPS ones 2023-11-20 10:30:12 +01:00
drivers hwmon: (acpi_power_meter) Fix 4.29 MW bug 2023-12-13 18:18:13 +01:00
fs ovl: skip overlayfs superblocks at global sync 2023-12-08 08:44:27 +01:00
include of: Add missing 'Return' section in kerneldoc comments 2023-12-13 18:18:11 +01:00
init x86/mm: Initialize text poking earlier 2023-08-08 19:56:36 +02:00
ipc ipc/sem: Fix dangling sem_array access in semtimedop race 2022-12-08 11:23:06 +01:00
kernel tracing: Fix a warning when allocating buffered events fails 2023-12-13 18:18:13 +01:00
lib kobject: Fix slab-out-of-bounds in fill_kobj_path() 2023-11-08 11:23:38 +01:00
LICENSES
mm mm/cma: use nth_page() in place of direct struct page manipulation 2023-11-28 16:50:19 +00:00
net bpf: sockmap, updating the sg structure should also update curr 2023-12-13 18:18:13 +01:00
samples samples/bpf: Fix buffer overflow in tcp_basertt 2023-07-27 08:37:07 +02:00
scripts kconfig: fix memory leak from range properties 2023-12-13 18:18:10 +01:00
security ima: detect changes to the backing overlay file 2023-12-08 08:44:27 +01:00
sound ASoC: wm_adsp: fix memleak in wm_adsp_buffer_populate 2023-12-13 18:18:13 +01:00
tools tools/power/turbostat: Fix a knl bug 2023-11-28 16:50:17 +00:00
usr
virt KVM: Destroy target device if coalesced MMIO unregistration fails 2023-03-11 16:44:01 +01:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS iio: stx104: Move to addac subdirectory 2023-08-30 16:27:12 +02:00
Makefile Linux 5.4.263 2023-12-08 08:44:28 +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.