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Merged
rousskov merged 2 commits into from
Feb 16, 2024
Merged

Default to full gdb backtraces #21

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31fc9f6
Default to full backtraces
rousskov Feb 14, 2024
861b20a
fixup: Remove discussion about "bt full" speed
rousskov Feb 16, 2024
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22 changes: 10 additions & 12 deletions docs/SquidFaq/BugReporting.md
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Original file line number Diff line number Diff line change
Expand Up @@ -33,12 +33,11 @@ checks. If one of those checks fail, Squid calls abort() to generate a
core dump.

If you have a core dump file, then use gdb to extract a stack trace from
the core using a "bt full" command (if supported) or a "backtrace"
command (can be typed as "bt" and is always supported, but gives less
information):
the core using a `backtrace full` command (if supported) or a `backtrace`
command (always supported, but gives less information):

% gdb /usr/local/squid/sbin/squid core
gdb> backtrace
gdb> backtrace full

Many people report that Squid doesn't leave a coredump anywhere. This
may be due to one of the following reasons:
Expand Down Expand Up @@ -67,7 +66,7 @@ may be due to one of the following reasons:
Core was generated by `(squid) -D'.
Program terminated with signal 6, Aborted.

(gdb) bt
(gdb) backtrace full
#0 0x006ad7a2 in _dl_sysinfo_int80 () from /lib/ld-linux.so.2
#1 0x006ed7a5 in raise () from /lib/tls/libc.so.6
#2 0x006ef209 in abort () from /lib/tls/libc.so.6
Expand Down Expand Up @@ -163,7 +162,7 @@ Once you have located the core dump file, use a debugger such as *dbx*
or *gdb* to generate a stack trace:

% gdb /usr/local/squid/sbin/squid core
gdb> backtrace
gdb> backtrace full

If possible, you might keep the coredump file around for a day or two.
It is often helpful if we can ask you to send additional debugger
Expand Down Expand Up @@ -225,7 +224,7 @@ handle SIGSEGV stop
handle SIGABRT stop
run -NYCX
[wait for crash]
backtrace
backtrace full
quit
```

Expand All @@ -248,7 +247,7 @@ handle SIGKILL pass
handle SIGSEGV stop
handle SIGABRT stop
run -NYCd3
backtrace
backtrace full
quit
EOF
while sleep 2; do
Expand Down Expand Up @@ -283,7 +282,7 @@ handle SIGABRT stop

attach [worker PID]
[wait for crash]
backtrace
backtrace full
detach
quit
```
Expand All @@ -296,11 +295,10 @@ stuck in a busy loop, and/or you want to know what your Squid is doing

1. To dump the current stack using gdb:
```
sudo gdb -n -batch -ex backtrace -pid <PID>
sudo gdb -n -batch -ex 'backtrace full' -pid <PID>
```
You may not need/want the `-n` (i.e. do not load gdb initialization
files) option. Using `'backtrace full'` instead of `backtrace` will
give even more info but might be a tad slower.
files) option.
1. To dump the current stack using pstack(1):
```
sudo pstack <PID>
Expand Down