Messages in this thread | | | From | Mark Gross <> | Subject | Re: [PATCH] multithreaded coredumps for elf exeecutables | Date | Wed, 20 Mar 2002 11:14:56 -0500 |
| |
I've only JUST started on the Itanium version of this patch. In my initial testing, after hacking around some of the compilation issues, I do get a type of process freezing when attempting this. Could be this bug.
Thanks for the tip ;)
--mgross
On Wednesday 20 March 2002 01:37 pm, Daniel Jacobowitz wrote: > On Wed, Mar 20, 2002 at 11:36:30AM +0530, Vamsi Krishna S . wrote: > > There is serialization at higher level. We take a write lock > > on current->mm->mmap_sem at the beginning of elf_core_dump > > function which is released just before leaving the function. > > So, if one thread enters elf_core_dump and starts dumping core, > > no other thread (same mm) of the same process can start > > dumping. > > > > static int elf_core_dump(long signr, struct pt_regs * regs, struct file * > > file) { > > ... > > ... > > /* now stop all vm operations */ > > down_write(¤t->mm->mmap_sem); > > ... > > ... > > ... > > up_write(¤t->mm->mmap_sem); > > return has_dumped; > > } > > That's not a feature, it's a bug. You can't take the mmap_sem before > collecting thread status; it will cause a deadlock on at least ia64, > where some registers are collected from user memory. > > (Thanks to Manfred Spraul for explaining that to me.) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |