[Crash-utility] [PATCH] fix for "sys -c" option for certain vmcores
Hi Dave,
I don't know why this difference arises, but with certain kernel configurations,
the source file and line information of the schedule() function becomes the
following, not "/kernel/sched/core.c".
crash> sym schedule
ffffffffab0d3666 (T) schedule /share/src/linux-5.0.1/./arch/x86/include/asm/current.h:
15
This causes the "sys -c" option not to print the information of system calls,
and makes it very slow.
crash> sys -c | sh -c 'time cat'
NUM SYSTEM CALL FILE AND LINE NUMBER
0 __x64_sys_read
1 __x64_sys_write
2 __x64_sys_open
...
333 __x64_sys_io_pgetevents
334 __x64_sys_rseq
real 2m32.669s
user 0m0.002s
sys 0m0.022s
With this patch, the option can print the information in not too long time:
crash> sys -c | sh -c 'time cat'
NUM SYSTEM CALL FILE AND LINE NUMBER
0 __x64_sys_read ../fs/read_write.c: 588
1 __x64_sys_write ../fs/read_write.c: 610
2 __x64_sys_open ../fs/open.c: 1079
...
333 __x64_sys_io_pgetevents ../fs/aio.c: 2139
334 __x64_sys_rseq ../kernel/rseq.c: 308
real 0m10.905s
user 0m0.000s
sys 0m0.024s
Also, in dump_sys_call_table(), it looks like there is no need to call
get_build_directory() for each system call, so moving it out of the loop
makes it faster.
[without moving the get_build_directory()]
real 0m15.862s
user 0m0.003s
sys 0m0.020s
Signed-off-by: Kazuhito Hagio <k-hagio(a)ab.jp.nec.com>
---
kernel.c | 2 +-
symbols.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel.c b/kernel.c
index db25f22e4ec6..22909d28cefc 100644
--- a/kernel.c
+++ b/kernel.c
@@ -5679,6 +5679,7 @@ dump_sys_call_table(char *spec, int cnt)
fprintf(fp, "%s", sys_call_hdr);
+ get_build_directory(buf2);
for (i = 0, sct = sys_call_table; i < NR_syscalls; i++, sct++) {
if (!(scp = value_symbol(*sct))) {
if (confirmed || CRASHDEBUG(1)) {
@@ -5710,7 +5711,6 @@ dump_sys_call_table(char *spec, int cnt)
*/
sp = value_search(*sct, NULL);
spn = next_symbol(NULL, sp);
- get_build_directory(buf2);
for (addr = *sct; sp && spn && (addr < spn->value); addr++) {
BZERO(buf1, BUFSIZE);
diff --git a/symbols.c b/symbols.c
index 863d1f0a8e25..3ce8692fd397 100644
--- a/symbols.c
+++ b/symbols.c
@@ -4296,7 +4296,7 @@ get_build_directory(char *buf)
get_line_number(symbol_value("do_schedule"), buf, FALSE);
else
return NULL;
- if ((p = strstr(buf, "/kernel/")))
+ if ((p = strstr(buf, "/kernel/")) || (p = strstr(buf, "/./arch/")))
*p = NULLCHAR;
else
return(NULL);
--
2.18.1