[Valgrind-users] Can't extend stack during signal delivery : too small or bad protection modes

[Narayanan I. <na...@yo...>]

Hi,

While running the automated test suite (which has hundreds of tests) for my application with valgrind, I occasionally see failures like the following in some of the tests.

==29753== Can't extend stack to 0x1ffeec7948 during signal delivery for thread 1:
==29753==   too small or bad protection modes
==29753== 
==29753== Process terminating with default action of signal 11 (SIGSEGV): dumping core
==29753==  Access not within mapped region at address 0x1FFEEC7948
==29753==    at 0x4849FD8: strncpy (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==29753==    by 0x489AE7C: cli_get_sub_quals (sr_unix/cli_parse.c:593)
==29753==    by 0x489ABC3: parse_arg (sr_unix/cli_parse.c:0)
==29753==    by 0x489BD6E: parse_triggerfile_cmd (sr_unix/cli_parse.c:1128)
==29753==    by 0x4BD2377: trigger_parse (sr_unix/trigger_parse.c:1416)
==29753==    by 0x4B12152: trigger_update_rec (sr_unix/trigger_update.c:1386)
==29753==    by 0x4B16171: trigger_update_rec_helper (sr_unix/trigger_update.c:2171)
==29753==    by 0x4B163B9: trigger_update (sr_unix/trigger_update.c:2224)
==29753==    by 0x4B86385: op_fnztrigger (sr_port/op_fnztrigger.c:248)
==29753==    by 0x5ABA384: _ydboctoplanhelpers (in YDBOcto/build/src/_ydbocto.so)
==29753==    by 0x1774F1EF: ???
==29753==    by 0xAAAAAAAAAAAAAAA9: ???
==29753==  If you believe this happened as a result of a stack
==29753==  overflow in your program's main thread (unlikely but
==29753==  possible), you can try to increase the size of the
==29753==  main thread stack using the --main-stacksize= flag.
==29753==  The main thread stack size used in this run was 268435456.
==29753== Invalid write of size 8
==29753==    at 0x483A124: _vgnU_freeres (in /usr/libexec/valgrind/vgpreload_core-amd64-linux.so)
==29753==  Address 0x1ffeec8808 is on thread 1's stack

If I rerun just the failing test, it passes fine. Every time the list of tests that fail keeps changing. If I run the test without valgrind, it passes all the time.

Originally I got a failure with the --main-stacksize set to 16Mb so I bumped it to 256Mb. And I still keep getting this failure at different tests. I also set the ulimit for stacksize to 256Mb just in case and I still see the failures.

The application is a single-threaded application and I know for sure it does not use anywhere near 256Mb of stack space. The stack trace shown above keeps changing across the many random failures but in all of those stack traces, I believe only around .25Mb of stack space would be used at the most. 

In this application, a SIGALRM signal would happen every 1 second or so. The application does not set up any alternate stack (i.e. no sigaltstack() call). Not sure if that can be related to the random failure or not.

This is on a Ubuntu 20.04 system. And my application was compiled with gcc.

Not sure how to debug this further. Any help in this regard is appreciated.

Thanks,
Narayanan.