Subject: mm: Fixup all fault handlers to check current->pagefault_disable
From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 17 Mar 2011 11:32:28 +0100
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/3.12/patches-3.12.1-rt4.tar.xz

Necessary for decoupling pagefault disable from preempt count.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
 arch/alpha/mm/fault.c      |    2 +-
 arch/arm/mm/fault.c        |    2 +-
 arch/avr32/mm/fault.c      |    3 ++-
 arch/cris/mm/fault.c       |    2 +-
 arch/frv/mm/fault.c        |    2 +-
 arch/ia64/mm/fault.c       |    2 +-
 arch/m32r/mm/fault.c       |    2 +-
 arch/m68k/mm/fault.c       |    2 +-
 arch/microblaze/mm/fault.c |    2 +-
 arch/mips/mm/fault.c       |    2 +-
 arch/mn10300/mm/fault.c    |    2 +-
 arch/parisc/mm/fault.c     |    2 +-
 arch/powerpc/mm/fault.c    |    2 +-
 arch/s390/mm/fault.c       |    6 ++++--
 arch/score/mm/fault.c      |    2 +-
 arch/sh/mm/fault.c         |    2 +-
 arch/sparc/mm/fault_32.c   |    2 +-
 arch/sparc/mm/fault_64.c   |    2 +-
 arch/tile/mm/fault.c       |    2 +-
 arch/um/kernel/trap.c      |    2 +-
 arch/x86/mm/fault.c        |    2 +-
 arch/xtensa/mm/fault.c     |    2 +-
 22 files changed, 26 insertions(+), 23 deletions(-)

--- a/arch/alpha/mm/fault.c
+++ b/arch/alpha/mm/fault.c
@@ -107,7 +107,7 @@ do_page_fault(unsigned long address, uns
 
 	/* If we're in an interrupt context, or have no user context,
 	   we must not take the fault.  */
-	if (!mm || in_atomic())
+	if (!mm || in_atomic() || current->pagefault_disabled)
 		goto no_context;
 
 #ifdef CONFIG_ALPHA_LARGE_VMALLOC
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -277,7 +277,7 @@ do_page_fault(unsigned long addr, unsign
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_atomic() || !mm)
+	if (in_atomic() || !mm || current->pagefault_disabled)
 		goto no_context;
 
 	if (user_mode(regs))
--- a/arch/avr32/mm/fault.c
+++ b/arch/avr32/mm/fault.c
@@ -81,7 +81,8 @@ asmlinkage void do_page_fault(unsigned l
 	 * If we're in an interrupt or have no user context, we must
 	 * not take the fault...
 	 */
-	if (in_atomic() || !mm || regs->sr & SYSREG_BIT(GM))
+	if (in_atomic() || !mm || regs->sr & SYSREG_BIT(GM) ||
+	    current->pagefault_disabled)
 		goto no_context;
 
 	local_irq_enable();
--- a/arch/cris/mm/fault.c
+++ b/arch/cris/mm/fault.c
@@ -113,7 +113,7 @@ do_page_fault(unsigned long address, str
 	 * user context, we must not take the fault.
 	 */
 
-	if (in_atomic() || !mm)
+	if (in_atomic() || !mm || current->pagefault_disabled)
 		goto no_context;
 
 	if (user_mode(regs))
--- a/arch/frv/mm/fault.c
+++ b/arch/frv/mm/fault.c
@@ -78,7 +78,7 @@ asmlinkage void do_page_fault(int datamm
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_atomic() || !mm)
+	if (in_atomic() || !mm || current->pagefault_disabled)
 		goto no_context;
 
 	if (user_mode(__frame))
--- a/arch/ia64/mm/fault.c
+++ b/arch/ia64/mm/fault.c
@@ -96,7 +96,7 @@ ia64_do_page_fault (unsigned long addres
 	/*
 	 * If we're in an interrupt or have no user context, we must not take the fault..
 	 */
-	if (in_atomic() || !mm)
+	if (in_atomic() || !mm || current->pagefault_disabled)
 		goto no_context;
 
 #ifdef CONFIG_VIRTUAL_MEM_MAP
--- a/arch/m32r/mm/fault.c
+++ b/arch/m32r/mm/fault.c
@@ -114,7 +114,7 @@ asmlinkage void do_page_fault(struct pt_
 	 * If we're in an interrupt or have no user context or are running in an
 	 * atomic region then we must not take the fault..
 	 */
-	if (in_atomic() || !mm)
+	if (in_atomic() || !mm || current->pagefault_disabled
 		goto bad_area_nosemaphore;
 
 	if (error_code & ACE_USERMODE)
--- a/arch/m68k/mm/fault.c
+++ b/arch/m68k/mm/fault.c
@@ -85,7 +85,7 @@ int do_page_fault(struct pt_regs *regs,
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_atomic() || !mm)
+	if (in_atomic() || !mm || current->pagefault_disabled)
 		goto no_context;
 
 	if (user_mode(regs))
--- a/arch/microblaze/mm/fault.c
+++ b/arch/microblaze/mm/fault.c
@@ -107,7 +107,7 @@ void do_page_fault(struct pt_regs *regs,
 	if ((error_code & 0x13) == 0x13 || (error_code & 0x11) == 0x11)
 		is_write = 0;
 
-	if (unlikely(in_atomic() || !mm)) {
+	if (unlikely(in_atomic() || !mm || current->pagefault_disabled)) {
 		if (kernel_mode(regs))
 			goto bad_area_nosemaphore;
 
--- a/arch/mips/mm/fault.c
+++ b/arch/mips/mm/fault.c
@@ -89,7 +89,7 @@ static void __kprobes __do_page_fault(st
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_atomic() || !mm)
+	if (in_atomic() || !mm || current->pagefault_disabled)
 		goto bad_area_nosemaphore;
 
 	if (user_mode(regs))
--- a/arch/mn10300/mm/fault.c
+++ b/arch/mn10300/mm/fault.c
@@ -168,7 +168,7 @@ asmlinkage void do_page_fault(struct pt_
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_atomic() || !mm)
+	if (in_atomic() || !mm || current->pagefault_disabled)
 		goto no_context;
 
 	if ((fault_code & MMUFCR_xFC_ACCESS) == MMUFCR_xFC_ACCESS_USR)
--- a/arch/parisc/mm/fault.c
+++ b/arch/parisc/mm/fault.c
@@ -177,7 +177,7 @@ void do_page_fault(struct pt_regs *regs,
 	int fault;
 	unsigned int flags;
 
-	if (in_atomic())
+	if (in_atomic() || current->pagefault_disabled)
 		goto no_context;
 
 	tsk = current;
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -261,7 +261,7 @@ int __kprobes do_page_fault(struct pt_re
 	if (!arch_irq_disabled_regs(regs))
 		local_irq_enable();
 
-	if (in_atomic() || mm == NULL) {
+	if (in_atomic() || mm == NULL || current->pagefault_disabled) {
 		if (!user_mode(regs)) {
 			rc = SIGSEGV;
 			goto bail;
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -296,7 +296,8 @@ static inline int do_exception(struct pt
 	 * user context.
 	 */
 	fault = VM_FAULT_BADCONTEXT;
-	if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm))
+	if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm ||
+		    tsk->pagefault_disabled))
 		goto out;
 
 	address = trans_exc_code & __FAIL_ADDR_MASK;
@@ -442,7 +443,8 @@ void __kprobes do_asce_exception(struct
 	clear_tsk_thread_flag(current, TIF_PER_TRAP);
 
 	trans_exc_code = regs->int_parm_long;
-	if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm))
+	if (unlikely(!user_space_fault(trans_exc_code) || in_atomic() || !mm ||
+		     current->pagefault_disabled()));
 		goto no_context;
 
 	down_read(&mm->mmap_sem);
--- a/arch/score/mm/fault.c
+++ b/arch/score/mm/fault.c
@@ -73,7 +73,7 @@ asmlinkage void do_page_fault(struct pt_
 	* If we're in an interrupt or have no user
 	* context, we must not take the fault..
 	*/
-	if (in_atomic() || !mm)
+	if (in_atomic() || !mm || current->pagefault_disabled)
 		goto bad_area_nosemaphore;
 
 	if (user_mode(regs))
--- a/arch/sh/mm/fault.c
+++ b/arch/sh/mm/fault.c
@@ -438,7 +438,7 @@ asmlinkage void __kprobes do_page_fault(
 	 * If we're in an interrupt, have no user context or are running
 	 * in an atomic region then we must not take the fault:
 	 */
-	if (unlikely(in_atomic() || !mm)) {
+	if (unlikely(in_atomic() || !mm || current->pagefault_disabled)) {
 		bad_area_nosemaphore(regs, error_code, address);
 		return;
 	}
--- a/arch/sparc/mm/fault_32.c
+++ b/arch/sparc/mm/fault_32.c
@@ -199,7 +199,7 @@ asmlinkage void do_sparc_fault(struct pt
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_atomic() || !mm)
+	if (in_atomic() || !mm || current->pagefault_disabled)
 		goto no_context;
 
 	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
--- a/arch/sparc/mm/fault_64.c
+++ b/arch/sparc/mm/fault_64.c
@@ -322,7 +322,7 @@ asmlinkage void __kprobes do_sparc64_fau
 	 * If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_atomic() || !mm)
+	if (in_atomic() || !mm || current->pagefault_enabled)
 		goto intr_or_no_mm;
 
 	perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address);
--- a/arch/tile/mm/fault.c
+++ b/arch/tile/mm/fault.c
@@ -357,7 +357,7 @@ static int handle_page_fault(struct pt_r
 	 * If we're in an interrupt, have no user context or are running in an
 	 * atomic region then we must not take the fault.
 	 */
-	if (in_atomic() || !mm) {
+	if (in_atomic() || !mm || current->pagefault_disabled) {
 		vma = NULL;  /* happy compiler */
 		goto bad_area_nosemaphore;
 	}
--- a/arch/um/kernel/trap.c
+++ b/arch/um/kernel/trap.c
@@ -38,7 +38,7 @@ int handle_page_fault(unsigned long addr
 	 * If the fault was during atomic operation, don't take the fault, just
 	 * fail.
 	 */
-	if (in_atomic())
+	if (in_atomic() || current->pagefault_disabled)
 		goto out_nosemaphore;
 
 	if (is_user)
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1094,7 +1094,7 @@ static void __kprobes
 	 * If we're in an interrupt, have no user context or are running
 	 * in an atomic region then we must not take the fault:
 	 */
-	if (unlikely(in_atomic() || !mm)) {
+	if (unlikely(in_atomic() || !mm || current->pagefault_disabled)) {
 		bad_area_nosemaphore(regs, error_code, address);
 		return;
 	}
--- a/arch/xtensa/mm/fault.c
+++ b/arch/xtensa/mm/fault.c
@@ -57,7 +57,7 @@ void do_page_fault(struct pt_regs *regs)
 	/* If we're in an interrupt or have no user
 	 * context, we must not take the fault..
 	 */
-	if (in_atomic() || !mm) {
+	if (in_atomic() || !mm || current->pagefault_disabled) {
 		bad_page_fault(regs, address, SIGSEGV);
 		return;
 	}