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2b70702917
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Namhyung Kim 2b70702917 perf tools: Remove evsel__handle_error_quirks() 
The evsel__handle_error_quirks() is to fixup invalid event attributes on
some architecture based on the error code.  Currently it's only used for
AMD to disable precise_ip not to use IBS which has more restrictions.

But the commit c33aea446b changed call evsel__precise_ip_fallback
for any errors so there's no difference with the above function.  To
make matter worse, it caused a problem with branch stack on Zen3.

The IBS doesn't support branch stack so it should use a regular core
PMU event.  The default event is set precise_max and it starts with 3.
And evsel__precise_ip_fallback() tries with it and reduces the level one
by one.  At last it tries with 0 but it also failed on Zen3 since the
branch stack is not supported for the cycles event.

At this point, evsel__precise_ip_fallback() restores the original
precise_ip value (3) in the hope that it can succeed with other modifier
(like exclude_kernel).  Then evsel__handle_error_quirks() see it has
precise_ip != 0 and make it retry with 0.  This created an infinite
loop.

Before:

  $ perf record -b -vv |& grep removing
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  removing precise_ip on AMD
  ...

After:

  $ perf record -b true
  Error:
  Failure to open event 'cycles:P' on PMU 'cpu' which will be removed.
  Invalid event (cycles:P) in per-thread mode, enable system wide with '-a'.
  Error:
  Failure to open any events for recording.

Fixes: c33aea446b ("perf tools: Fix precise_ip fallback logic")
Tested-by: Chun-Tse Shao <ctshao@google.com>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Link: https://lore.kernel.org/r/20250410010252.402221-1-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
2025-04-11 09:22:49 -07:00
arch A set of final cleanups for the timer subsystem: 2025-04-06 08:35:37 -07:00
block treewide: Switch/rename to timer_delete[_sync]() 2025-04-05 10:30:12 +02:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto This push fixes reverts the multibuffer hash testing as it is buggy. 2025-04-02 09:14:59 -07:00
Documentation A set of final cleanups for the timer subsystem: 2025-04-06 08:35:37 -07:00
drivers A set of final cleanups for the timer subsystem: 2025-04-06 08:35:37 -07:00
fs Miscellaneous scheduler fixes/updates: 2025-04-06 10:44:58 -07:00
include A set of final cleanups for the timer subsystem: 2025-04-06 08:35:37 -07:00
init Miscellaneous scheduler fixes/updates: 2025-04-06 10:44:58 -07:00
io_uring io_uring: always do atomic put from iowq 2025-04-03 08:31:57 -06:00
ipc treewide: const qualify ctl_tables where applicable 2025-01-28 13:48:37 +01:00
kernel Fix a perf events time accounting bug. 2025-04-06 10:48:12 -07:00
lib Kbuild updates for v6.15 2025-04-05 15:46:50 -07:00
LICENSES LICENSES: add 0BSD license text 2024-09-01 20:43:24 -07:00
mm Disable SLUB_TINY for build testing 2025-04-06 10:00:04 -07:00
net treewide: Switch/rename to timer_delete[_sync]() 2025-04-05 10:30:12 +02:00
rust Kbuild updates for v6.15 2025-04-05 15:46:50 -07:00
samples treewide: Switch/rename to timer_delete[_sync]() 2025-04-05 10:30:12 +02:00
scripts Disable SLUB_TINY for build testing 2025-04-06 10:00:04 -07:00
security mseal sysmap: kernel config and header change 2025-04-01 15:17:14 -07:00
sound soundwire fix for 6.15-rc1 2025-04-06 12:04:53 -07:00
tools perf tools: Remove evsel__handle_error_quirks() 2025-04-11 09:22:49 -07:00
usr kbuild: hdrcheck: fix cross build with clang 2025-03-05 04:06:45 +09:00
virt ARM: 2025-03-25 14:22:07 -07:00
.clang-format clang-format: Update with v6.11-rc1's for_each macro list 2024-08-02 13:20:31 +02:00
.clippy.toml rust: give Clippy the minimum supported Rust version 2025-01-10 00:17:25 +01:00
.cocciconfig
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: Retire Ralf Baechle 2024-11-12 15:48:59 +01:00
.gitattributes
.gitignore kbuild: Create intermediate vmlinux build with relocations preserved 2025-03-17 00:29:50 +09:00
.mailmap mailmap: add an entry for Nicolas Schier 2025-04-01 15:20:45 -07:00
.rustfmt.toml
COPYING
CREDITS Including fixes from netfilter. 2025-04-04 09:15:35 -07:00
Kbuild drm: ensure drm headers are self-contained and pass kernel-doc 2025-02-12 10:44:43 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS Kbuild updates for v6.15 2025-04-05 15:46:50 -07:00
Makefile Linux 6.15-rc1 2025-04-06 13:11:33 -07:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

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 reStructuredText 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.