Attachment 278331 Details for Bug 408321 – patch to fix stack corruption in futex code

[patch] patch to fix stack corruption in futex code

futex-stack-signal-fix.patch (text/plain), 2.65 KB, created by Steven Rostedt on 2007-12-05 14:24:19 UTC

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Creator: Steven Rostedt

Created: 2007-12-05 14:24:19 UTC

Size: 2.65 KB

patch

obsolete

> include/linux/thread_info.h |   15 ++++++++++++++-
> kernel/futex.c              |   25 +++++++++++++------------
> 2 files changed, 27 insertions(+), 13 deletions(-)
>
>Index: linux-2.6.21-rt-hack/include/linux/thread_info.h
>===================================================================
>--- linux-2.6.21-rt-hack.orig/include/linux/thread_info.h
>+++ linux-2.6.21-rt-hack/include/linux/thread_info.h
>@@ -7,12 +7,25 @@
> #ifndef _LINUX_THREAD_INFO_H
> #define _LINUX_THREAD_INFO_H
> 
>+#include <linux/types.h>
>+
> /*
>  * System call restart block. 
>  */
> struct restart_block {
> 	long (*fn)(struct restart_block *);
>-	unsigned long arg0, arg1, arg2, arg3;
>+	union {
>+		struct {
>+			unsigned long arg0, arg1, arg2, arg3;
>+		};
>+		/* For futex_wait */
>+		struct {
>+			u32 *uaddr;
>+			u32 val;
>+			u32 flags;
>+			u64 time;
>+		} fu;
>+	};
> };
> 
> extern long do_no_restart_syscall(struct restart_block *parm);
>Index: linux-2.6.21-rt-hack/kernel/futex.c
>===================================================================
>--- linux-2.6.21-rt-hack.orig/kernel/futex.c
>+++ linux-2.6.21-rt-hack/kernel/futex.c
>@@ -1414,9 +1414,9 @@ static int fixup_pi_state_owner(u32 __us
> 
> /*
>  * In case we must use restart_block to restart a futex_wait,
>- * we encode in the 'arg3' shared capability
>+ * we encode in the 'flags' shared capability
>  */
>-#define ARG3_SHARED  1
>+#define FLAGS_SHARED  1
> 
> static long futex_wait_restart(struct restart_block *restart);
> 
>@@ -1630,12 +1630,13 @@ static int futex_wait(u32 __user *uaddr,
> 		struct restart_block *restart;
> 		restart = &current_thread_info()->restart_block;
> 		restart->fn = futex_wait_restart;
>-		restart->arg0 = (unsigned long)uaddr;
>-		restart->arg1 = (unsigned long)val;
>-		restart->arg2 = (unsigned long)abs_time;
>-		restart->arg3 = 0;
>+		restart->fu.uaddr = (u32*)uaddr;
>+		restart->fu.val = val;
>+		restart->fu.time = abs_time->tv64;
>+		restart->fu.flags = 0;
>+
> 		if (fshared)
>-			restart->arg3 |= ARG3_SHARED;
>+			restart->fu.flags |= FLAGS_SHARED;
> 		return -ERESTART_RESTARTBLOCK;
> 	}
> 
>@@ -1650,15 +1651,15 @@ static int futex_wait(u32 __user *uaddr,
> 
> static long futex_wait_restart(struct restart_block *restart)
> {
>-	u32 __user *uaddr = (u32 __user *)restart->arg0;
>-	u32 val = (u32)restart->arg1;
>-	ktime_t *abs_time = (ktime_t *)restart->arg2;
>+	u32 __user *uaddr = (u32 __user *)restart->fu.uaddr;
> 	struct rw_semaphore *fshared = NULL;
>+	ktime_t t;
> 
>+	t.tv64 = restart->fu.time;
> 	restart->fn = do_no_restart_syscall;
>-	if (restart->arg3 & ARG3_SHARED)
>+	if (restart->fu.flags & FLAGS_SHARED)
> 		fshared = &current->mm->mmap_sem;
>-	return (long)futex_wait(uaddr, fshared, val, abs_time);
>+	return (long)futex_wait(uaddr, fshared, restart->fu.val, &t);
> }
> 
>

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Attachments on bug 408321: 275431 | 278331