linux-hardened/lib/bust_spinlocks.c
Jan Beulich 004429956b handle recursive calls to bust_spinlocks()
Various architectures may call bust_spinlocks() recursively; the function
itself, however, doesn't appear to be meant to be called in this manner.
Nevertheless, this doesn't appear to be a problem as long as
bust_spinlocks(0) doesn't get called twice in a row (otherwise,
unblank_screen() may enter the scheduler).  However, at least on i386 die()
has been capable of returning (and on other architectures this should
really be that way, too) when notify_die() returns NOTIFY_STOP.

Short of getting a reply to a respective query, this patch makes
bust_spinlocks() increment/decrement oops_in_progress, and wake klogd only
when the count drops back to zero.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-17 08:42:56 -07:00

30 lines
588 B
C

/*
* lib/bust_spinlocks.c
*
* Provides a minimal bust_spinlocks for architectures which don't have one of their own.
*
* bust_spinlocks() clears any spinlocks which would prevent oops, die(), BUG()
* and panic() information from reaching the user.
*/
#include <linux/kernel.h>
#include <linux/spinlock.h>
#include <linux/tty.h>
#include <linux/wait.h>
#include <linux/vt_kern.h>
void __attribute__((weak)) bust_spinlocks(int yes)
{
if (yes) {
++oops_in_progress;
} else {
#ifdef CONFIG_VT
unblank_screen();
#endif
if (--oops_in_progress == 0)
wake_up_klogd();
}
}