mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
synced 2026-05-04 10:56:06 -04:00
5172672da0
The 'len' returned by grab_bb() includes an extra MAXINSN bytes to allow
for the last instruction, so the the final 'offs' will not be 'len'.
Fix the error condition logic accordingly.
Before:
$ perf record -e '{intel_pt//,cpu/mem_inst_retired.all_loads,aux-sample-size=8192/pp}:u' grep -rqs jhgjhg /boot
[ perf record: Woken up 19 times to write data ]
[ perf record: Captured and wrote 2.274 MB perf.data ]
$ perf script -F +brstackinsn --xed --itrace=i1usl100 | head
grep 13759 [002] 8091.310257: 1862 instructions:uH: 5641d58069eb bmexec+0x86b (/bin/grep)
bmexec+2485:
00005641d5806b35 jnz 0x5641d5806bd0 # MISPRED
00005641d5806bd0 movzxb (%r13,%rdx,1), %eax
00005641d5806bd6 add %rdi, %rax
00005641d5806bd9 movzxb -0x1(%rax), %edx
00005641d5806bdd cmp %rax, %r14
00005641d5806be0 jnb 0x5641d58069c0 # MISPRED
mismatch of LBR data and executable
00005641d58069c0 movzxb (%r13,%rdx,1), %edi
After:
$ perf script -F +brstackinsn --xed --itrace=i1usl100 | head
grep 13759 [002] 8091.310257: 1862 instructions:uH: 5641d58069eb bmexec+0x86b (/bin/grep)
bmexec+2485:
00005641d5806b35 jnz 0x5641d5806bd0 # MISPRED
00005641d5806bd0 movzxb (%r13,%rdx,1), %eax
00005641d5806bd6 add %rdi, %rax
00005641d5806bd9 movzxb -0x1(%rax), %edx
00005641d5806bdd cmp %rax, %r14
00005641d5806be0 jnb 0x5641d58069c0 # MISPRED
00005641d58069c0 movzxb (%r13,%rdx,1), %edi
00005641d58069c6 add %rax, %rdi
Fixes: e98df280bc ("perf script brstackinsn: Fix recovery from LBR/binary mismatch")
Reported-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/20191127095631.15663-1-adrian.hunter@intel.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.