341e0e9f59
'perf record; with callchain recording fails as below
in powerpc:
./perf record -a -gR sleep 10
./perf report
perf: Segmentation fault
gdb trace points to thread__find_map
0 0x00000000101df314 in atomic_cmpxchg (newval=1818846826, oldval=1818846827, v=0x1001a8f3) at /home/athira/linux/tools/include/asm-generic/atomic-gcc.h:70
1 refcount_sub_and_test (i=1, r=0x1001a8f3) at /home/athira/linux/tools/include/linux/refcount.h:135
2 refcount_dec_and_test (r=0x1001a8f3) at /home/athira/linux/tools/include/linux/refcount.h:148
3 map__put (map=0x1001a8b3) at util/map.c:311
4 0x000000001016842c in __map__zput (map=0x7fffffffa368) at util/map.h:190
5 thread__find_map (thread=0x105b92f0, cpumode=<optimized out>, addr=13835058055283572736, al=al@entry=0x7fffffffa358) at util/event.c:582
6 0x000000001016882c in thread__find_symbol (thread=<optimized out>, cpumode=<optimized out>, addr=<optimized out>, al=0x7fffffffa358) at util/event.c:656
7 0x00000000102e12b4 in arch_skip_callchain_idx (thread=<optimized out>, chain=<optimized out>) at arch/powerpc/util/skip-callchain-idx.c:255
8 0x00000000101d3bf4 in thread__resolve_callchain_sample (thread=0x105b92f0, cursor=0x1053d160, evsel=<optimized out>, sample=0x7fffffffa908, parent=0x7fffffffa778, root_al=0x7fffffffa710,
max_stack=<optimized out>) at util/machine.c:2940
9 0x00000000101cd210 in sample__resolve_callchain (sample=<optimized out>, cursor=<optimized out>, parent=<optimized out>, evsel=<optimized out>, al=<optimized out>, max_stack=<optimized out>)
at util/callchain.c:1112
10 0x000000001022a9d8 in hist_entry_iter__add (iter=0x7fffffffa750, al=0x7fffffffa710, max_stack_depth=<optimized out>, arg=0x7fffffffbbd0) at util/hist.c:1232
11 0x0000000010056d98 in process_sample_event (tool=0x7fffffffbbd0, event=0x7ffff6223c38, sample=0x7fffffffa908, evsel=<optimized out>, machine=0x10524ef8) at builtin-report.c:332
Here arch_skip_callchain_idx calls thread__find_symbol and which
invokes thread__find_map with uninitialised "addr_location".
Snippet:
thread__find_symbol(thread, PERF_RECORD_MISC_USER, ip, &al);
Recent change with commit 0dd5041c9a0eaf8c ("perf addr_location: Add
init/exit/copy functions") , introduced "maps__zput" in the function
thread__find_map. This could result in segfault while accessing
uninitialised map from "struct addr_location". Fix this by adding
addr_location__init and addr_location__exit in arch_skip_callchain_idx.
Fixes: 0dd5041c9a0eaf8c ("perf addr_location: Add init/exit/copy functions")
Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Disha Goel <disgoel@linux.vnet.ibm.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kajol Jain <kjain@linux.ibm.com>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: linuxppc-dev@lists.ozlabs.org
Link: https://lore.kernel.org/r/20230724165815.17810-1-atrajeev@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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.