forked from Minki/linux
mainlining shenanigans
0c7296cad6
Lockdep noticed the following 3-way lockup scenario: sys_perf_event_open() perf_event_alloc() perf_try_init_event() #0 ctx = perf_event_ctx_lock_nested(1) perf_swevent_init() swevent_hlist_get() #1 mutex_lock(&pmus_lock) perf_event_init_cpu() #1 mutex_lock(&pmus_lock) #2 mutex_lock(&ctx->mutex) sys_perf_event_open() mutex_lock_double() #2 mutex_lock() #0 mutex_lock_nested() And while we need that perf_event_ctx_lock_nested() for HW PMUs such that they can iterate the sibling list, trying to match it to the available counters, the software PMUs need do no such thing. Exclude them. In particular the swevent triggers the above invertion, while the tpevent PMU triggers a more elaborate one through their event_mutex. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vince Weaver <vincent.weaver@maine.edu> Cc: linux-kernel@vger.kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org> |
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| Documentation | ||
| drivers | ||
| firmware | ||
| fs | ||
| include | ||
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| ipc | ||
| kernel | ||
| lib | ||
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| samples | ||
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| .cocciconfig | ||
| .get_maintainer.ignore | ||
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| COPYING | ||
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| README | ||
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.