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author | Hugo Wen <wenhug@amazon.com> | 2023-03-24 16:06:11 +0000 |
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committer | Vicențiu-Marian Ciorbaru <vicentiu@mariadb.org> | 2023-04-01 10:07:42 +0300 |
commit | 3b6424407025aad39b00e60bd0d711b67272513f (patch) | |
tree | c989a3ba318c3b6bc45e616511475d1badf4286c | |
parent | eaebe8b5600b144c51a9405de42a70bd4b710987 (diff) | |
download | mariadb-git-3b6424407025aad39b00e60bd0d711b67272513f.tar.gz |
Handle meaningless addr2line results and increase timeout
MariaDB server prints the stack information if a crash happens.
It traverses the stack frames in function `print_with_addr_resolve`.
For *EACH* frame, it tries to parse the file name and line number of the
frame using `addr2line`, or prints `backtrace_symbols_fd` if `addr2line`
fails.
1. Logic in `addr_resolve` function uses addr2line to get the file name
and line numbers. It has a timeout of 500ms to wait for the response
from addr2line. However, that's not enough on small instances
especially if the debug information is in a separate file or
compressed.
Increase the timeout to 5 seconds to support some edge cases, as
experiments showed addr2line may take 2-3 seconds on some frames.
2. While parsing a frame inside of a shared library using `addr2line`,
the file name and line numbers could be `??`, empty or `0` if the
debug info is not loaded.
It's easy to reproduce when glibc-debuginfo is not installed.
Instead of printing a meaningless frame like:
:0(__GI___poll)[0x1505e9197639]
...
??:0(__libc_start_main)[0x7ffff6c8913a]
We want to print the frame information using `backtrace_symbols_fd`,
with the shared library name and a hexadecimal offset.
Stacktrace example on a real instance with this commit:
/lib64/libc.so.6(__poll+0x49)[0x145cbf71a639]
...
/lib64/libc.so.6(__libc_start_main+0xea)[0x7f4d0034d13a]
`addr_resolve` has considered the case of meaningless combination of
file name and line number returned by `addr2line`. e.g. `??:?`
However, conditions like `:0` and `??:0` are not handled. So now the
function will rollback to `backtrace_symbols_fd` in above cases.
All new code of the whole pull request, including one or several files
that are either new files or modified ones, are contributed under the
BSD-new license. I am contributing on behalf of my employer Amazon Web
Services, Inc.
-rw-r--r-- | mysys/my_addr_resolve.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/mysys/my_addr_resolve.c b/mysys/my_addr_resolve.c index ac1bdae187c..52fcaaf67bb 100644 --- a/mysys/my_addr_resolve.c +++ b/mysys/my_addr_resolve.c @@ -252,10 +252,10 @@ int my_addr_resolve(void *ptr, my_addr_loc *loc) return 3; - /* 500 ms should be plenty of time for addr2line to issue a response. */ + /* 5000 ms should be plenty of time for addr2line to issue a response. */ /* Read in a loop till all the output from addr2line is complete. */ while (parsed == total_bytes_read && - (ret= poll(&poll_fds, 1, 500))) + (ret= poll(&poll_fds, 1, 5000))) { /* error during poll */ if (ret < 0) @@ -299,7 +299,8 @@ int my_addr_resolve(void *ptr, my_addr_loc *loc) loc->line= atoi(output + line_number_start); /* Addr2line was unable to extract any meaningful information. */ - if (strcmp(loc->file, "??") == 0) + if ((strcmp(loc->file, "??") == 0 || strcmp(loc->file, "") == 0) && + (loc->func[0] == '?' || loc->line == 0)) return 6; loc->file= strip_path(loc->file); |