On Wed, May 27, 2015 at 1:56 PM, Jan Stancek <jstan...@redhat.com> wrote: > On Wed, May 27, 2015 at 01:27:13AM -0400, Jarod Wilson wrote: >> On May 26, 2015, at 5:24 PM, Alexey Dobriyan <adobri...@gmail.com> wrote: >> >> Should have tested on more than just x86, it appears. We've started >> >> hammering on this internally across all arches, and its exploded >> >> multiple times on ppc64 now: >> >> >> >> [ 2717.074699] ------------[ cut here ]------------ >> >> [ 2717.074787] kernel BUG at fs/proc/base.c:244! >> > >> >> OE-------------- 3.10.0-255.el7.ppc64.debug #1 >> > >> > Which BUG_ON is this? >> > >> > BUG_ON(*pos < 0); >> > BUG_ON(arg_start > arg_end); >> > BUG_ON(env_start > env_end); >> > > Is create_elf_tables() taking mm->mmap_sem when it's initialising > env_start/end?
No, and it wasn't needed before checkpoint/restart (prctl(PR_SET_MM ...)). Fields were write-once, now they aren't. C/R is doing down_read() in prctl_set_mm() which is an obvious bug. Check "if (!mm->arg_end)" is safeguard exactly against new process not having ARGV/ENVP fields completely initialized. I didn't understand what it does exactly, now it's clear. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/