Red Hat Bugzilla – Bug 170052
elf_core_dump is a stack hog (1192 bytes)
Last modified: 2007-11-30 17:07:08 EST
Please note: I'm submitting this as a suggestion from an RHEL3 user, not as
a corporate request from SGI.
Description of problem:
elf_core_dump uses over 1k of stack (about 20% of what's available) on ia32,
due to large stack variables. Dumping core to a filesystem that is over
stacked volume managers, or over a networked filesytem could cause the stack
A patch went into the 2.5 series to remedy this:
I've attached a backport of this patch that gets elf_core_dump down under 200
bytes. It was quick work and could bear some scrutiny that I'm sure you'd
give it anyway. :)
Version-Release number of selected component (if applicable):
Created attachment 119685 [details]
elf_core_dump stack reduction patch
er, try that patch attachment one more time.
Eric, still an issue?
Do you want to push as a RH employee now?
Yep looks like it's still an issue...
c0191f50: 55 push %ebp
c0191f51: 57 push %edi
c0191f52: 56 push %esi
c0191f53: 53 push %ebx
c0191f54: bb 00 e0 ff ff mov $0xffffe000,%ebx
c0191f59: 21 e3 and %esp,%ebx
c0191f5b: 81 ec ac 04 00 00 sub $0x4ac,%esp
1196 bytes... ouch.
I'll see what people think of fixing this. Maybe I can come up with a non-cxfs
The problem isn't the stack above, it's what's below -
... and down into whatever stacked IO stuff you may have
OTOH 2.4.21 still has 8k to work withg, right, so it's not quite as bad (which
is probably why this -was- cleaned up upstream in 2.6)
If nobody's hit it in the wild on RHEL3, perhaps it's not worth worrying about
at this point.
If this hasn't been an issue for our customers yet, it's probably not worth the