Patch "um: Fix possible deadlock in sig_handler_common()" has been added to the 4.7-stable tree

Patch "um: Fix possible deadlock in sig_handler_common()" has been added to the 4.7-stable tree

[gregkh]

This is a note to let you know that I've just added the patch titled

    um: Fix possible deadlock in sig_handler_common()

to the 4.7-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     um-fix-possible-deadlock-in-sig_handler_common.patch
and it can be found in the queue-4.7 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@vger.kernel.org> know about it.


>From 57a05d83b16710aff30510c33768df7ab17e0b4a Mon Sep 17 00:00:00 2001
From: Richard Weinberger <richard@nod.at>
Date: Sun, 12 Jun 2016 22:03:16 +0200
Subject: um: Fix possible deadlock in sig_handler_common()

From: Richard Weinberger <richard@nod.at>

commit 57a05d83b16710aff30510c33768df7ab17e0b4a upstream.

We are in atomic context and must not sleep.
Sleeping here is possible since malloc() maps
to kmalloc() with GFP_KERNEL.

Fixes: b6024b21 ("um: extend fpstate to _xstate to support YMM registers")
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 arch/um/os-Linux/signal.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/arch/um/os-Linux/signal.c
+++ b/arch/um/os-Linux/signal.c
@@ -15,6 +15,7 @@
 #include <kern_util.h>
 #include <os.h>
 #include <sysdep/mcontext.h>
+#include <um_malloc.h>
 
 void (*sig_info[NSIG])(int, struct siginfo *, struct uml_pt_regs *) = {
 	[SIGTRAP]	= relay_signal,
@@ -32,7 +33,7 @@ static void sig_handler_common(int sig,
 	struct uml_pt_regs *r;
 	int save_errno = errno;
 
-	r = malloc(sizeof(struct uml_pt_regs));
+	r = uml_kmalloc(sizeof(struct uml_pt_regs), UM_GFP_ATOMIC);
 	if (!r)
 		panic("out of memory");
 
@@ -91,7 +92,7 @@ static void timer_real_alarm_handler(mco
 {
 	struct uml_pt_regs *regs;
 
-	regs = malloc(sizeof(struct uml_pt_regs));
+	regs = uml_kmalloc(sizeof(struct uml_pt_regs), UM_GFP_ATOMIC);
 	if (!regs)
 		panic("out of memory");
 


Patches currently in stable-queue which might be from richard@nod.at are

queue-4.7/um-fix-possible-deadlock-in-sig_handler_common.patch
queue-4.7/ubi-fix-race-condition-between-ubi-device-creation-and-udev.patch
queue-4.7/ubi-fix-early-logging.patch
queue-4.7/ubi-make-volume-resize-power-cut-aware.patch