4

I'd like to inspect some global variables before a crash happens. The issue only reproduces on a certain stack trace and setting a breakpoint on the innermost function (or any other from the stack) will not get me close enough.

Can I achieve the result of breaking only when the top of the stack contains something like this ?

#0 __GI_connect
#1 curl_connect
#2 get_file
#3 init_assets

Just doing

b init_assets
c
b get_file
c
...

doesn't work since init_assets is called multiple times and it doesn't call curl every time, so gdb will break in unrelated code that uses curl.

Later edit: another way is: 

b inner_func
ignore 1 10000
r
# app crashes
info b

Breakpoint 1 has been hit 10 times.

Then you remove the breakpoint, add it back and only ignore 9 times. When you run the app again, gdb will stop on the 10th time -- when inner_func crashes.

You can also record the app in mozilla's rr if the execution varies too much.

4

1 回答 1

12

您可以将条件断点与$_caller_is便利功能一起使用。像这样的东西：

(gdb) break connect
Breakpoint 1 at 0x7ffff7ee6820
(gdb) cond 1 $_caller_is("curl_connect") && $_caller_is("get_file", 2) && $_caller_is("init_assets", 3)
于 2019-03-26T13:31:54.143 回答