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More bad backtraces through nanosleep
- From: Daniel Jacobowitz <drow at mvista dot com>
- To: gdb at sources dot redhat dot com
- Date: Sun, 7 Sep 2003 15:22:32 -0400
- Subject: More bad backtraces through nanosleep
This is a little unfortunate...
Glibc with NPTL uses DWARF-2 unwind information to describe syscall
wrappers, because the NPTL implementation of cancellation uses dwarf2
unwinding. However, glibc with LinuxThreads does not. So if you're running
a multi-threaded LinuxThreads application, when we hit a syscall we're
likely to get completely lost. We can't reasonably expect GDB's prologue
unwinder to figure out nanosleep; the function has no prologue, and then
pushes things onto the stack inside CENABLE/CDISABLE.
Libc folks, would there be any disadvantages besides space to adding unwind
info to the cancellable syscall wrappers in LT also? How would you feel
about such a patch?
--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer