diff options
| -rw-r--r-- | arch/um/kernel/trap.c | 24 | ||||
| -rw-r--r-- | arch/x86/mm/fault.c | 24 | ||||
| -rw-r--r-- | include/linux/mm.h | 5 | ||||
| -rw-r--r-- | mm/oom_kill.c | 94 |
4 files changed, 84 insertions, 63 deletions
diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c index 44e49041949..7384d8accfe 100644 --- a/arch/um/kernel/trap.c +++ b/arch/um/kernel/trap.c @@ -64,11 +64,10 @@ good_area: do { int fault; -survive: + fault = handle_mm_fault(mm, vma, address, is_write); if (unlikely(fault & VM_FAULT_ERROR)) { if (fault & VM_FAULT_OOM) { - err = -ENOMEM; goto out_of_memory; } else if (fault & VM_FAULT_SIGBUS) { err = -EACCES; @@ -104,18 +103,14 @@ out: out_nosemaphore: return err; -/* - * We ran out of memory, or some other thing happened to us that made - * us unable to handle the page fault gracefully. - */ out_of_memory: - if (is_global_init(current)) { - up_read(&mm->mmap_sem); - yield(); - down_read(&mm->mmap_sem); - goto survive; - } - goto out; + /* + * We ran out of memory, call the OOM killer, and return the userspace + * (which will retry the fault, or kill us if we got oom-killed). + */ + up_read(&mm->mmap_sem); + pagefault_out_of_memory(); + return 0; } static void bad_segv(struct faultinfo fi, unsigned long ip) @@ -214,9 +209,6 @@ unsigned long segv(struct faultinfo fi, unsigned long ip, int is_user, si.si_addr = (void __user *)address; current->thread.arch.faultinfo = fi; force_sig_info(SIGBUS, &si, current); - } else if (err == -ENOMEM) { - printk(KERN_INFO "VM: killing process %s\n", current->comm); - do_exit(SIGKILL); } else { BUG_ON(err != -EFAULT); si.si_signo = SIGSEGV; diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c index 57ec8c86a87..9e268b6b204 100644 --- a/arch/x86/mm/fault.c +++ b/arch/x86/mm/fault.c @@ -667,7 +667,6 @@ void __kprobes do_page_fault(struct pt_regs *regs, unsigned long error_code) if (unlikely(in_atomic() || !mm)) goto bad_area_nosemaphore; -again: /* * When running in the kernel we expect faults to occur only to * addresses in user space. All other faults represent errors in the @@ -859,25 +858,14 @@ no_context: oops_end(flags, regs, sig); #endif -/* - * We ran out of memory, or some other thing happened to us that made - * us unable to handle the page fault gracefully. - */ out_of_memory: + /* + * We ran out of memory, call the OOM killer, and return the userspace + * (which will retry the fault, or kill us if we got oom-killed). + */ up_read(&mm->mmap_sem); - if (is_global_init(tsk)) { - yield(); - /* - * Re-lookup the vma - in theory the vma tree might - * have changed: - */ - goto again; - } - - printk("VM: killing process %s\n", tsk->comm); - if (error_code & PF_USER) - do_group_exit(SIGKILL); - goto no_context; + pagefault_out_of_memory(); + return; do_sigbus: up_read(&mm->mmap_sem); diff --git a/include/linux/mm.h b/include/linux/mm.h index aaa8b843be2..4a3d28c8644 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -717,6 +717,11 @@ static inline int page_mapped(struct page *page) #define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS) +/* + * Can be called by the pagefault handler when it gets a VM_FAULT_OOM. + */ +extern void pagefault_out_of_memory(void); + #define offset_in_page(p) ((unsigned long)(p) & ~PAGE_MASK) extern void show_free_areas(void); diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 558f9afe6e4..c592965dab2 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -509,6 +509,69 @@ void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask) spin_unlock(&zone_scan_mutex); } +/* + * Must be called with tasklist_lock held for read. + */ +static void __out_of_memory(gfp_t gfp_mask, int order) +{ + if (sysctl_oom_kill_allocating_task) { + oom_kill_process(current, gfp_mask, order, 0, NULL, + "Out of memory (oom_kill_allocating_task)"); + + } else { + unsigned long points; + struct task_struct *p; + +retry: + /* + * Rambo mode: Shoot down a process and hope it solves whatever + * issues we may have. + */ + p = select_bad_process(&points, NULL); + + if (PTR_ERR(p) == -1UL) + return; + + /* Found nothing?!?! Either we hang forever, or we panic. */ + if (!p) { + read_unlock(&tasklist_lock); + panic("Out of memory and no killable processes...\n"); + } + + if (oom_kill_process(p, gfp_mask, order, points, NULL, + "Out of memory")) + goto retry; + } +} + +/* + * pagefault handler calls into here because it is out of memory but + * doesn't know exactly how or why. + */ +void pagefault_out_of_memory(void) +{ + unsigned long freed = 0; + + blocking_notifier_call_chain(&oom_notify_list, 0, &freed); + if (freed > 0) + /* Got some memory back in the last second. */ + return; + + if (sysctl_panic_on_oom) + panic("out of memory from page fault. panic_on_oom is selected.\n"); + + read_lock(&tasklist_lock); + __out_of_memory(0, 0); /* unknown gfp_mask and order */ + read_unlock(&tasklist_lock); + + /* + * Give "p" a good chance of killing itself before we + * retry to allocate memory. + */ + if (!test_thread_flag(TIF_MEMDIE)) + schedule_timeout_uninterruptible(1); +} + /** * out_of_memory - kill the "best" process when we run out of memory * @zonelist: zonelist pointer @@ -522,8 +585,6 @@ void clear_zonelist_oom(struct zonelist *zonelist, gfp_t gfp_mask) */ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order) { - struct task_struct *p; - unsigned long points = 0; unsigned long freed = 0; enum oom_constraint constraint; @@ -544,7 +605,7 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order) switch (constraint) { case CONSTRAINT_MEMORY_POLICY: - oom_kill_process(current, gfp_mask, order, points, NULL, + oom_kill_process(current, gfp_mask, order, 0, NULL, "No available memory (MPOL_BIND)"); break; @@ -553,35 +614,10 @@ void out_of_memory(struct zonelist *zonelist, gfp_t gfp_mask, int order) panic("out of memory. panic_on_oom is selected\n"); /* Fall-through */ case CONSTRAINT_CPUSET: - if (sysctl_oom_kill_allocating_task) { - oom_kill_process(current, gfp_mask, order, points, NULL, - "Out of memory (oom_kill_allocating_task)"); - break; - } -retry: - /* - * Rambo mode: Shoot down a process and hope it solves whatever - * issues we may have. - */ - p = select_bad_process(&points, NULL); - - if (PTR_ERR(p) == -1UL) - goto out; - - /* Found nothing?!?! Either we hang forever, or we panic. */ - if (!p) { - read_unlock(&tasklist_lock); - panic("Out of memory and no killable processes...\n"); - } - - if (oom_kill_process(p, gfp_mask, order, points, NULL, - "Out of memory")) - goto retry; - + __out_of_memory(gfp_mask, order); break; } -out: read_unlock(&tasklist_lock); /* |