yaowenbin 64f18d2d04 perf top: Fix TUI exit screen refresh race condition
When the following command is executed several times, a coredump file is
generated.

	$ timeout -k 9 5 perf top -e task-clock
	*******
	*******
	*******
	0.01%  [kernel]                  [k] __do_softirq
	0.01%  libpthread-2.28.so        [.] __pthread_mutex_lock
	0.01%  [kernel]                  [k] __ll_sc_atomic64_sub_return
	double free or corruption (!prev) perf top --sort comm,dso
	timeout: the monitored command dumped core

When we terminate "perf top" using sending signal method,
SLsmg_reset_smg() called. SLsmg_reset_smg() resets the SLsmg screen
management routines by freeing all memory allocated while it was active.

However SLsmg_reinit_smg() maybe be called by another thread.

SLsmg_reinit_smg() will free the same memory accessed by
SLsmg_reset_smg(), thus it results in a double free.

SLsmg_reinit_smg() is called already protected by ui__lock, so we fix
the problem by adding pthread_mutex_trylock of ui__lock when calling
SLsmg_reset_smg().

Signed-off-by: Wenyu Liu <liuwenyu7@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: wuxu.wu@huawei.com
Link: http://lore.kernel.org/lkml/a91e3943-7ddc-f5c0-a7f5-360f073c20e6@huawei.com
Signed-off-by: Hewenliang <hewenliang4@huawei.com>
Signed-off-by: yaowenbin <yaowenbin1@huawei.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-01-02 11:46:44 -03:00
2021-12-26 13:17:17 -08:00

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.
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