[Bug libgcc/57405] New: Using printf in signal handler with alternate stack generates a SIGSEGV

[jkf at research dot att.com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57405

            Bug ID: 57405
           Summary: Using printf in signal handler with alternate stack
                    generates a SIGSEGV
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libgcc
          Assignee: unassigned at gcc dot gnu.org
          Reporter: jkf at research dot att.com

Created attachment 30185
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=30185&action=edit
requested bug information and gdb session showing failure

When using several printf's in a sigaction signal handler and alternate stacks
generates a SIGSEGV:
Program received signal SIGSEGV, Segmentation fault.
0x0000003b8ce480ac in _IO_vfprintf_internal (s=<value optimized out>,
    format=<value optimized out>, ap=<value optimized out>) at vfprintf.c:1641
1641              process_string_arg (((struct printf_spec *) NULL));

This is independent of the size of the alternate signal stack. I have tried it
with 4 * SIGSTKSZ and same error at same line when alternate signal stack is is
SIGSTKSZ (8k).

Attached is file with requested information and output of gdb debug session of
program execution.