aboutsummaryrefslogtreecommitdiffstats
path: root/arch/i386/kernel/process.c
diff options
context:
space:
mode:
authorStas Sergeev <stsp@aknet.ru>2005-04-16 18:24:01 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 18:24:01 -0400
commit5df240826c90afdc7956f55a004ea6b702df9203 (patch)
tree1782971ae77b3d902fdf56e77e9649b3b6c48ca4 /arch/i386/kernel/process.c
parente493073d8d053429fbb42331b57a95dd0d61cadb (diff)
[PATCH] fix crash in entry.S restore_all
Fix the access-above-bottom-of-stack crash. 1. Allows to preserve the valueable optimization 2. Works for NMIs 3. Doesn't care whether or not there are more of the like instances where the stack is left empty. 4. Seems to work for me without the crashes:) (akpm: this is still under discussion, although I _think_ it's OK. You might want to hold off) Signed-off-by: Stas Sergeev <stsp@aknet.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'arch/i386/kernel/process.c')
-rw-r--r--arch/i386/kernel/process.c12
1 files changed, 11 insertions, 1 deletions
diff --git a/arch/i386/kernel/process.c b/arch/i386/kernel/process.c
index c36fedf40e95..36145efc61b5 100644
--- a/arch/i386/kernel/process.c
+++ b/arch/i386/kernel/process.c
@@ -405,7 +405,17 @@ int copy_thread(int nr, unsigned long clone_flags, unsigned long esp,
405 childregs->esp = esp; 405 childregs->esp = esp;
406 406
407 p->thread.esp = (unsigned long) childregs; 407 p->thread.esp = (unsigned long) childregs;
408 p->thread.esp0 = (unsigned long) (childregs+1); 408 /*
409 * The below -8 is to reserve 8 bytes on top of the ring0 stack.
410 * This is necessary to guarantee that the entire "struct pt_regs"
411 * is accessable even if the CPU haven't stored the SS/ESP registers
412 * on the stack (interrupt gate does not save these registers
413 * when switching to the same priv ring).
414 * Therefore beware: accessing the xss/esp fields of the
415 * "struct pt_regs" is possible, but they may contain the
416 * completely wrong values.
417 */
418 p->thread.esp0 = (unsigned long) (childregs+1) - 8;
409 419
410 p->thread.eip = (unsigned long) ret_from_fork; 420 p->thread.eip = (unsigned long) ret_from_fork;
411 421