[PATCH 3.12 20/39] m68k/mm: Check for mm != NULL in do_page_fault() debug code

From	Jiri Slaby <jslaby@suse.cz>
Newsgroups	linux.kernel
Subject	[PATCH 3.12 20/39] m68k/mm: Check for mm != NULL in do_page_fault() debug code
Date	2016-01-25 13:00 +0100
Message-ID	<qUNYn-3kJ-47@gated-at.bofh.it> (permalink)
References	<qUNYl-3kJ-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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From: Geert Uytterhoeven <geert@linux-m68k.org>

3.12-stable review patch.  If anyone has any objections, please let me know.

===============

commit 4e25c0e92f8eaf69bc51d1d523bcb7268e7dd162 upstream.

When DEBUG is enabled, do_page_fault() may dereference a NULL pointer,
causing recursive bus errors.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Oliver Neukum <ONeukum@suse.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 arch/m68k/mm/fault.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c
index f0eef0491f77..97136b5e47e0 100644
--- a/arch/m68k/mm/fault.c
+++ b/arch/m68k/mm/fault.c
@@ -77,8 +77,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
 
 #ifdef DEBUG
 	printk ("do page fault:\nregs->sr=%#x, regs->pc=%#lx, address=%#lx, %ld, %p\n",
-		regs->sr, regs->pc, address, error_code,
-		current->mm->pgd);
+		regs->sr, regs->pc, address, error_code, mm ? mm->pgd : NULL);
 #endif
 
 	/*
-- 
2.7.0

Thread

[PATCH 3.12 01/39] efi: Disable interrupts around EFI calls, not in the epilog/prolog calls Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 02/39] tools: Add a "make all" rule Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 26/39] udp: properly support MSG_PEEK with truncated buffers Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 24/39] KEYS: Fix race between read and revoke Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 22/39] sctp: Prevent soft lockup when sctp_accept() is called during a timeout event Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 28/39] xen/gntdev: Grant maps should not be subject to NUMA balancing Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 36/39] MAINTAINERS: Add public mailing list for ARC Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 27/39] x86/signal: Fix restart_syscall number for x32 tasks Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 16/39] staging/dgnc: fix info leak in ioctl Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 37/39] ARC: Fix silly typo in MAINTAINERS file commit 30b9dbee895ff0d5cbf155bd1ef3f0f5992bca6f upstream. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 25/39] KEYS: Fix keyring ref leak in join_session_keyring() Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 32/39] x86/boot: Double BOOT_HEAP_SIZE to 64KB Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 38/39] isdn_ppp: Add checks for allocation failure in isdn_ppp_open() Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 12/39] block: Always check queue limits for cloned requests Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 20/39] m68k/mm: Check for mm != NULL in do_page_fault() debug code Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 18/39] m32r: fix potential NULL-pointer dereference Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 15/39] module: remove MODULE_GENERIC_TABLE Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 23/39] USB: quirks: Fix another ELAN touchscreen Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 17/39] pm: use GFP_ATOMIC when pm core call this function Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 39/39] ppp, slip: Validate VJ compression slot parameters completely Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 30/39] KVM: PPC: Book3S HV: Prohibit setting illegal transaction state in MSR Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 21/39] m68k/mac: Make SCC reset work more reliably Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 34/39] ALSA: hda - Add Intel Lewisburg device IDs Audio Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 04/39] dlm: make posix locks interruptible Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 35/39] ALSA: hda - Apply pin fixup for HP ProBook 6550b Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 14/39] qla2xxx: Fix hardware lock/unlock issue causing kernel panic. Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 29/39] x86/xen: don't reset vcpu_info on a cancelled suspend Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:00 +0100
  [PATCH 3.12 10/39] drm/i915: Fix SRC_COPY width on 830/845g Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:10 +0100
  [PATCH 3.12 07/39] route: Use ipv4_mtu instead of raw rt_pmtu Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:10 +0100
  [PATCH 3.12 13/39] Input: aiptek - fix crash on detecting device without endpoints Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:10 +0100
  [PATCH 3.12 05/39] PCI: Drop "setting latency timer" messages Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:10 +0100
  [PATCH 3.12 11/39] lpfc: Fix null ndlp dereference in target_reset_handler Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:10 +0100
  [PATCH 3.12 09/39] ring-buffer: Always run per-cpu ring buffer resize with schedule_work_on() Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:10 +0100
  [PATCH 3.12 06/39] ipv4: Don't increase PMTU with Datagram Too Big message. Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:10 +0100
  [PATCH 3.12 03/39] ALSA: hda - Fix noise problems on Thinkpad T440s Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:10 +0100
  [PATCH 3.12 08/39] SUNRPC: Fix oops when trace sunrpc_task events in nfs client Jiri Slaby <jslaby@suse.cz> - 2016-01-25 13:10 +0100

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