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author | Markus Metzger <markus.t.metzger@intel.com> | 2016-10-14 09:08:01 +0200 |
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committer | Markus Metzger <markus.t.metzger@intel.com> | 2016-11-14 10:15:42 +0100 |
commit | db58b3735f45345c06cb9a14d0f83f5b26c1ebf3 (patch) | |
tree | cbcf6405feb64c5e7ba7f141d739b7f1036a9e8d /binutils/dlltool.c | |
parent | 80bb3407f6891aff5dbed5b2fd5c3dae8f227319 (diff) | |
download | binutils-db58b3735f45345c06cb9a14d0f83f5b26c1ebf3.zip binutils-db58b3735f45345c06cb9a14d0f83f5b26c1ebf3.tar.gz binutils-db58b3735f45345c06cb9a14d0f83f5b26c1ebf3.tar.bz2 |
btrace: read entire aux buffer
The data_head of a perf event data buffer grows indefinitely. Users are
expected to compute data_head % data_size to find the location inside the perf
event data buffer.
The aux_head of a perf event aux buffer wraps around and always stays within the
perf event aux buffer.
Well, at least that's the behaviour for BTS and PT - where BTS uses the data
buffer and PT the aux buffer.
GDB does not read beyond data_head or aux_head. This is OK for BTS but wrong
for PT. It causes only a portion of the trace to be considered by GDB. In the
extreme case, the buffer may appear (almost) empty.
Thanks to Tim Wiederhake <tim.wiederhake@intel.com> for reporting the anomaly.
Change it to read the entire aux buffer for PT. The buffer is initially zero so
any extra zeroes we read before aux_head wraps around the first time will be
ignored when searching for the first PSB packet in order to synchronize onto the
trace stream.
gdb/
* nat/linux-btrace.c (perf_event_read): Allow data_head < size.
* nat/linux-btrace.c (perf_event_read_all): Do not adjust size.
Change-Id: If4f8049a2080a5f16f336309450b32a3eb1e3ec9
Diffstat (limited to 'binutils/dlltool.c')
0 files changed, 0 insertions, 0 deletions