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Date: Thu, 07 Oct 2010 18:10:04 +0100
From: Al Viro <viro@....linux.org.uk>
To: linux-m68k@...r.kernel.org
Cc: linux-kernel@...r.kernel.org
Subject: [PATCH 5/6] m68k: if we fail to set sigframe up, just leave regs
alone...
Same principle as with the previous patch - do not destroy the
state if sigframe setup fails. Incidentally, it's actually
_less_ work - we don't need to go through adjust_stack dance
on failure if we don't touch regs->stkadj until we know we'd
written sigframe out.
Signed-off-by: Al Viro <viro@...iv.linux.org.uk>
---
arch/m68k/kernel/signal.c | 44 ++++++++++++++++++++++++++++++--------------
1 files changed, 30 insertions(+), 14 deletions(-)
diff --git a/arch/m68k/kernel/signal.c b/arch/m68k/kernel/signal.c
index a6dd614..16ea319 100644
--- a/arch/m68k/kernel/signal.c
+++ b/arch/m68k/kernel/signal.c
@@ -761,10 +761,8 @@ static int setup_frame (int sig, struct k_sigaction *ka,
frame = get_sigframe(ka, regs, sizeof(*frame) + fsize);
- if (fsize) {
+ if (fsize)
err |= copy_to_user (frame + 1, regs + 1, fsize);
- regs->stkadj = fsize;
- }
err |= __put_user((current_thread_info()->exec_domain
&& current_thread_info()->exec_domain->signal_invmap
@@ -794,11 +792,21 @@ static int setup_frame (int sig, struct k_sigaction *ka,
push_cache ((unsigned long) &frame->retcode);
- /* Set up registers for signal handler */
+ /*
+ * Set up registers for signal handler. All the state we are about
+ * to destroy is successfully copied to sigframe.
+ */
wrusp ((unsigned long) frame);
regs->pc = (unsigned long) ka->sa.sa_handler;
-adjust_stack:
+ /*
+ * This is subtle; if we build more than one sigframe, all but the
+ * first one will see frame format 0 and have fsize == 0, so we won't
+ * screw stkadj.
+ */
+ if (fsize)
+ regs->stkadj = fsize;
+
/* Prepare to skip over the extra stuff in the exception frame. */
if (regs->stkadj) {
struct pt_regs *tregs =
@@ -813,11 +821,11 @@ adjust_stack:
tregs->pc = regs->pc;
tregs->sr = regs->sr;
}
- return err;
+ return 0;
give_sigsegv:
force_sigsegv(sig, current);
- goto adjust_stack;
+ return err;
}
static int setup_rt_frame (int sig, struct k_sigaction *ka, siginfo_t *info,
@@ -837,10 +845,8 @@ static int setup_rt_frame (int sig, struct k_sigaction *ka, siginfo_t *info,
frame = get_sigframe(ka, regs, sizeof(*frame));
- if (fsize) {
+ if (fsize)
err |= copy_to_user (&frame->uc.uc_extra, regs + 1, fsize);
- regs->stkadj = fsize;
- }
err |= __put_user((current_thread_info()->exec_domain
&& current_thread_info()->exec_domain->signal_invmap
@@ -882,11 +888,21 @@ static int setup_rt_frame (int sig, struct k_sigaction *ka, siginfo_t *info,
push_cache ((unsigned long) &frame->retcode);
- /* Set up registers for signal handler */
+ /*
+ * Set up registers for signal handler. All the state we are about
+ * to destroy is successfully copied to sigframe.
+ */
wrusp ((unsigned long) frame);
regs->pc = (unsigned long) ka->sa.sa_handler;
-adjust_stack:
+ /*
+ * This is subtle; if we build more than one sigframe, all but the
+ * first one will see frame format 0 and have fsize == 0, so we won't
+ * screw stkadj.
+ */
+ if (fsize)
+ regs->stkadj = fsize;
+
/* Prepare to skip over the extra stuff in the exception frame. */
if (regs->stkadj) {
struct pt_regs *tregs =
@@ -901,11 +917,11 @@ adjust_stack:
tregs->pc = regs->pc;
tregs->sr = regs->sr;
}
- return err;
+ return 0;
give_sigsegv:
force_sigsegv(sig, current);
- goto adjust_stack;
+ return err;
}
static inline void
--
1.5.6.5
--
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