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Steven Rostedt (Google) 2048fdc275 tracing: Decrement the snapshot if the snapshot trigger fails to register
Running the ftrace selftests caused the ring buffer mapping test to fail.
Investigating, I found that the snapshot counter would be incremented
every time a snapshot trigger was added, even if that snapshot trigger
failed.

 # cd /sys/kernel/tracing
 # echo "snapshot" > events/sched/sched_process_fork/trigger
 # echo "snapshot" > events/sched/sched_process_fork/trigger
 -bash: echo: write error: File exists

That second one that fails increments the snapshot counter but doesn't
decrement it. It needs to be decremented when the snapshot fails.

Link: https://lore.kernel.org/linux-trace-kernel/20240223013344.729055907@goodmis.org

Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Vincent Donnefort <vdonnefort@google.com>
Fixes: 16f7e48ffc53a ("tracing: Add snapshot refcount")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-03-18 10:33:05 -04:00
arch Probes updates for v6.9: 2024-03-14 16:16:33 -07:00
block Revert "dm: use queue_limits_set" 2024-03-11 17:11:28 -07:00
certs This update includes the following changes: 2023-11-02 16:15:30 -10:00
crypto crypto: lskcipher - Copy IV in lskcipher glue code always 2024-02-24 08:37:24 +08:00
Documentation tracing/user_events: Document multi-format flag 2024-03-18 10:13:16 -04:00
drivers cxl/trace: Properly initialize cxl_poison region name 2024-03-18 10:26:03 -04:00
fs NFSD: Fix nfsd_clid_class use of __string_len() macro 2024-03-18 10:17:41 -04:00
include tracing: Use EVENT_NULL_STR macro instead of open coding "(null)" 2024-03-18 10:33:04 -04:00
init Modules changes for v6.9-rc1 2024-03-13 12:40:58 -07:00
io_uring for-6.9/io_uring-20240310 2024-03-11 11:35:31 -07:00
ipc shm: Slim down dependencies 2023-12-20 19:26:31 -05:00
kernel tracing: Decrement the snapshot if the snapshot trigger fails to register 2024-03-18 10:33:05 -04:00
lib pci-v6.9-changes 2024-03-14 10:58:27 -07:00
LICENSES LICENSES: Add the copyleft-next-0.3.1 license 2022-11-08 15:44:01 +01:00
mm \n 2024-03-13 14:30:58 -07:00
net mm, slab: remove last vestiges of SLAB_MEM_SPREAD 2024-03-12 20:32:19 -07:00
rust arm64 updates for 6.9: 2024-03-14 15:35:42 -07:00
samples Landlock updates for v6.9-rc1 2024-03-14 16:00:27 -07:00
scripts arm64 updates for 6.9: 2024-03-14 15:35:42 -07:00
security lsm/stable-6.9 PR 20240314 2024-03-14 16:05:20 -07:00
sound sound updates for 6.9-rc1 2024-03-14 11:10:43 -07:00
tools selftests/user_events: Test multi-format events 2024-03-18 10:13:12 -04:00
usr Kbuild updates for v6.8 2024-01-18 17:57:07 -08:00
virt KVM: Make KVM_MEM_GUEST_MEMFD mutually exclusive with KVM_MEM_READONLY 2024-02-22 17:07:06 -08:00
.clang-format clang-format: Update with v6.7-rc4's for_each macro list 2023-12-08 23:54:38 +01:00
.cocciconfig
.editorconfig Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.get_maintainer.ignore Add Jeff Kirsher to .get_maintainer.ignore 2024-03-08 11:36:54 +00:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore Add .editorconfig file for basic formatting 2023-12-28 16:22:47 +09:00
.mailmap Networking changes for 6.9. 2024-03-12 17:44:08 -07:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS vfs-6.9.ntfs 2024-03-11 09:55:17 -07:00
Kbuild Kbuild updates for v6.1 2022-10-10 12:00:45 -07:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS arm64 updates for 6.9: 2024-03-14 15:35:42 -07:00
Makefile arm64 updates for 6.9: 2024-03-14 15:35:42 -07:00
README README: Fix spelling/capitalization 2024-02-12 16:42:13 -07:00

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.