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 c97f794..217bcbf 100644 --- a/arch/arm/mm/fault.c +++ b/arch/arm/mm/fault.c @@ -349,6 +349,13 @@ retry: 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 @@ retry: 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 6c8ba25..0bb7db4 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -288,6 +288,13 @@ retry: 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 @@ retry: 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 b2f2d2d..2ca27b0 100644 --- a/arch/avr32/mm/fault.c +++ b/arch/avr32/mm/fault.c @@ -228,9 +228,9 @@ no_context: */ 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 85df1cd..94d3a31 100644 --- a/arch/mips/mm/fault.c +++ b/arch/mips/mm/fault.c @@ -241,6 +241,8 @@ out_of_memory: * (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 089f398..b2f5adf 100644 --- a/arch/um/kernel/trap.c +++ b/arch/um/kernel/trap.c @@ -124,6 +124,8 @@ out_of_memory: * (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 f9b5c10..8ed3c45 100644 --- a/arch/unicore32/mm/fault.c +++ b/arch/unicore32/mm/fault.c @@ -278,6 +278,13 @@ retry: (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 @@ retry: 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 -- 2.7.4