From: Jeff Dike Date: Tue, 30 Jan 2007 22:36:17 +0000 (-0800) Subject: [PATCH] uml: fix signal frame alignment X-Git-Tag: v2.6.20-rc7~4 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=3896625d0badd53dbc34d584861a36ba7eb4613f;p=linux-2.6 [PATCH] uml: fix signal frame alignment Use the same signal frame alignment calculations as the underlying architecture. x86_64 appeared to do this, but the "- 8" was really subtracting 8 * sizeof(struct rt_sigframe) rather than 8 bytes. UML/i386 might have been OK, but I changed the calculation to match i386 just to be sure. Signed-off-by: Jeff Dike Cc: Cc: Adrian Bunk Cc: Paolo 'Blaisorblade' Giarrusso Acked-by: Antoine Martin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/arch/um/sys-i386/signal.c b/arch/um/sys-i386/signal.c index 0709fc6670..3f6acd6677 100644 --- a/arch/um/sys-i386/signal.c +++ b/arch/um/sys-i386/signal.c @@ -219,7 +219,8 @@ int setup_signal_stack_sc(unsigned long stack_top, int sig, unsigned long save_sp = PT_REGS_SP(regs); int err = 0; - stack_top &= -8UL; + /* This is the same calculation as i386 - ((sp + 4) & 15) == 0 */ + stack_top = ((stack_top + 4) & -16UL) - 4; frame = (struct sigframe __user *) stack_top - 1; if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame))) return 1; diff --git a/arch/um/sys-x86_64/signal.c b/arch/um/sys-x86_64/signal.c index 9edf114faf..af2f017617 100644 --- a/arch/um/sys-x86_64/signal.c +++ b/arch/um/sys-x86_64/signal.c @@ -191,8 +191,9 @@ int setup_signal_stack_si(unsigned long stack_top, int sig, struct task_struct *me = current; frame = (struct rt_sigframe __user *) - round_down(stack_top - sizeof(struct rt_sigframe), 16) - 8; - frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128); + round_down(stack_top - sizeof(struct rt_sigframe), 16); + /* Subtract 128 for a red zone and 8 for proper alignment */ + frame = (struct rt_sigframe __user *) ((unsigned long) frame - 128 - 8); if (!access_ok(VERIFY_WRITE, fp, sizeof(struct _fpstate))) goto out;