Bug 13331
| Summary: | FUTEX_LOCK_PI kills kernel | ||
|---|---|---|---|
| Product: | Process Management | Reporter: | Andreas Schwab (schwab) |
| Component: | Other | Assignee: | process_other |
| Status: | CLOSED CODE_FIX | ||
| Severity: | normal | CC: | alan, rjw, tglx |
| Priority: | P1 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Kernel Version: | 2.6.30-rc6 | Subsystem: | |
| Regression: | Yes | Bisected commit-id: | |
| Bug Depends on: | |||
| Bug Blocks: | 13070 | ||
| Attachments: | Testcase | ||
On which platform/architecture ? This is on ppc/ppc64. Ok, can reproduce on x86 as well (does not crash, boot loops forever). Fix below, but I'm wondering why the kernel is crashing. On x86 we run into an endless loop and I would have expected to see the same on PPC. Can you stick a dmesg output into the bugzilla please ? Thanks, tglx --- linux-2.6.orig/kernel/futex.c +++ linux-2.6/kernel/futex.c @@ -235,7 +235,7 @@ static int get_futex_key(u32 __user *uad } again: - err = get_user_pages_fast(address, 1, 0, &page); + err = get_user_pages_fast(address, 1, 1, &page); if (err < 0) return err; The kernel does not really crash, but it locks up in such a way that no userspace activity is possible any more. > The kernel does not really crash, but it locks up in such a way that no
> userspace activity is possible any more.
Ok, that's what I expected. Does the patch fix it for you as well ?
Thanks,
tglx
Yes, the patch works for me. Thomas is there a reason this isn't yet upstream with 2.6.30 close ? Handled-By : Thomas Gleixner <tglx@linutronix.de> Patch : http://bugzilla.kernel.org/show_bug.cgi?id=13331#c4 On Monday 25 May 2009, Peter Zijlstra wrote:
> On Sun, 2009-05-24 at 21:11 +0200, Rafael J. Wysocki wrote:
> > This message has been generated automatically as a part of a report
> > of recent regressions.
> >
> > The following bug entry is on the current list of known regressions
> > from 2.6.29. Please verify if it still should be listed and let me know
> > (either way).
> >
> >
> > Bug-Entry : http://bugzilla.kernel.org/show_bug.cgi?id=13331
> > Subject : FUTEX_LOCK_PI kills kernel
> > Submitter : Andreas Schwab <schwab@linux-m68k.org>
> > Date : 2009-05-17 09:51 (8 days old)
>
> commit 64d1304a64477629cb16b75491a77bafe6f86963
> Author: Thomas Gleixner <tglx@linutronix.de>
> Date: Mon May 18 21:20:10 2009 +0200
>
> futex: setup writeable mapping for futex ops which modify user space data
|
Created attachment 21386 [details] Testcase Calling futex with FUTEX_LOCK_PI crashes the kernel. Reverting e4dc5b7a36a49eff97050894cf1b3a9a02523717 (futex: clean up fault logic) fixes the bug.