From 871341023c771ad233620b7a1fb3d9c7031c4e5c Mon Sep 17 00:00:00 2001 From: Johannes Weiner Date: Thu, 12 Sep 2013 15:13:38 -0700 Subject: [PATCH] arch: mm: do not invoke OOM killer on kernel fault OOM Kernel faults are expected to handle OOM conditions gracefully (gup, uaccess etc.), so they should never invoke the OOM killer. Reserve this for faults triggered in user context when it is the only option. Most architectures already do this, fix up the remaining few. Signed-off-by: Johannes Weiner Reviewed-by: Michal Hocko Acked-by: KOSAKI Motohiro Cc: David Rientjes Cc: KAMEZAWA Hiroyuki Cc: azurIt Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/arm/mm/fault.c | 14 +++++++------- arch/arm64/mm/fault.c | 14 +++++++------- arch/avr32/mm/fault.c | 2 +- arch/mips/mm/fault.c | 2 ++ arch/um/kernel/trap.c | 2 ++ arch/unicore32/mm/fault.c | 14 +++++++------- 6 files changed, 26 insertions(+), 22 deletions(-) diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c index c97f7940cb95..217bcbfde42e 100644 --- a/arch/arm/mm/fault.c +++ b/arch/arm/mm/fault.c @@ -349,6 +349,13 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs) if (likely(!(fault & (VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS)))) return 0; + /* + * If we are in kernel mode at this point, we + * have no context to handle this fault with. + */ + if (!user_mode(regs)) + goto no_context; + if (fault & VM_FAULT_OOM) { /* * We ran out of memory, call the OOM killer, and return to @@ -359,13 +366,6 @@ do_page_fault(unsigned long addr, unsigned int fsr, struct pt_regs *regs) return 0; } - /* - * If we are in kernel mode at this point, we - * have no context to handle this fault with. - */ - if (!user_mode(regs)) - goto no_context; - if (fault & VM_FAULT_SIGBUS) { /* * We had some memory, but were unable to diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index 6c8ba25bf6bb..0bb7db41f4fe 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -288,6 +288,13 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, VM_FAULT_BADACCESS)))) return 0; + /* + * If we are in kernel mode at this point, we have no context to + * handle this fault with. + */ + if (!user_mode(regs)) + goto no_context; + if (fault & VM_FAULT_OOM) { /* * We ran out of memory, call the OOM killer, and return to @@ -298,13 +305,6 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, return 0; } - /* - * If we are in kernel mode at this point, we have no context to - * handle this fault with. - */ - if (!user_mode(regs)) - goto no_context; - if (fault & VM_FAULT_SIGBUS) { /* * We had some memory, but were unable to successfully fix up diff --git a/arch/avr32/mm/fault.c b/arch/avr32/mm/fault.c index b2f2d2d66849..2ca27b055825 100644 --- a/arch/avr32/mm/fault.c +++ b/arch/avr32/mm/fault.c @@ -228,9 +228,9 @@ asmlinkage void do_page_fault(unsigned long ecr, struct pt_regs *regs) */ out_of_memory: up_read(&mm->mmap_sem); - pagefault_out_of_memory(); if (!user_mode(regs)) goto no_context; + pagefault_out_of_memory(); return; do_sigbus: diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c index 85df1cd8d446..94d3a31ab144 100644 --- a/arch/mips/mm/fault.c +++ b/arch/mips/mm/fault.c @@ -241,6 +241,8 @@ static void __kprobes __do_page_fault(struct pt_regs *regs, unsigned long write, * (which will retry the fault, or kill us if we got oom-killed). */ up_read(&mm->mmap_sem); + if (!user_mode(regs)) + goto no_context; pagefault_out_of_memory(); return; diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c index 089f3987e273..b2f5adf838dd 100644 --- a/arch/um/kernel/trap.c +++ b/arch/um/kernel/trap.c @@ -124,6 +124,8 @@ int handle_page_fault(unsigned long address, unsigned long ip, * (which will retry the fault, or kill us if we got oom-killed). */ up_read(&mm->mmap_sem); + if (!is_user) + goto out_nosemaphore; pagefault_out_of_memory(); return 0; } diff --git a/arch/unicore32/mm/fault.c b/arch/unicore32/mm/fault.c index f9b5c10bccee..8ed3c4509d84 100644 --- a/arch/unicore32/mm/fault.c +++ b/arch/unicore32/mm/fault.c @@ -278,6 +278,13 @@ static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs) (VM_FAULT_ERROR | VM_FAULT_BADMAP | VM_FAULT_BADACCESS)))) return 0; + /* + * If we are in kernel mode at this point, we + * have no context to handle this fault with. + */ + if (!user_mode(regs)) + goto no_context; + if (fault & VM_FAULT_OOM) { /* * We ran out of memory, call the OOM killer, and return to @@ -288,13 +295,6 @@ static int do_pf(unsigned long addr, unsigned int fsr, struct pt_regs *regs) return 0; } - /* - * If we are in kernel mode at this point, we - * have no context to handle this fault with. - */ - if (!user_mode(regs)) - goto no_context; - if (fault & VM_FAULT_SIGBUS) { /* * We had some memory, but were unable to -- GitLab