From e26a7db9abe719df01e90be69774d7bf525c1078 Mon Sep 17 00:00:00 2001 From: Peter Xu Date: Wed, 1 Apr 2020 21:08:06 -0700 Subject: [PATCH] BACKPORT: mm: introduce fault_signal_pending() For most architectures, we've got a quick path to detect fatal signal after a handle_mm_fault(). Introduce a helper for that quick path. It cleans the current codes a bit so we don't need to duplicate the same check across archs. More importantly, this will be an unified place that we handle the signal immediately right after an interrupted page fault, so it'll be much easier for us if we want to change the behavior of handling signals later on for all the archs. Note that currently only part of the archs are using this new helper, because some archs have their own way to handle signals. In the follow up patches, we'll try to apply this helper to all the rest of archs. Another note is that the "regs" parameter in the new helper is not used yet. It'll be used very soon. Now we kept it in this patch only to avoid touching all the archs again in the follow up patches. [peterx@redhat.com: fix sparse warnings] Link: http://lkml.kernel.org/r/20200311145921.GD479302@xz-x1 Signed-off-by: Peter Xu Signed-off-by: Andrew Morton Tested-by: Brian Geffon Cc: Andrea Arcangeli Cc: Bobby Powers Cc: David Hildenbrand Cc: Denis Plotnikov Cc: "Dr . David Alan Gilbert" Cc: Hugh Dickins Cc: Jerome Glisse Cc: Johannes Weiner Cc: "Kirill A . Shutemov" Cc: Martin Cracauer Cc: Marty McFadden Cc: Matthew Wilcox Cc: Maya Gokhale Cc: Mel Gorman Cc: Mike Kravetz Cc: Mike Rapoport Cc: Pavel Emelyanov Link: http://lkml.kernel.org/r/20200220155353.8676-4-peterx@redhat.com Signed-off-by: Linus Torvalds (cherry picked from commit 4ef873226ceb9c7bf11a922caddc5698a24bcfaf) [Kalesh Singh: Resolve #include conflict in include/linux/sched/signal.h] Bug: 176847924 Signed-off-by: Kalesh Singh Change-Id: Ie9080d75c2cc22b1fd4b50755e9e61ad0ab677c2 --- arch/alpha/mm/fault.c | 2 +- arch/arm/mm/fault.c | 2 +- arch/hexagon/mm/vm_fault.c | 2 +- arch/ia64/mm/fault.c | 2 +- arch/m68k/mm/fault.c | 2 +- arch/microblaze/mm/fault.c | 2 +- arch/mips/mm/fault.c | 2 +- arch/nds32/mm/fault.c | 2 +- arch/nios2/mm/fault.c | 2 +- arch/openrisc/mm/fault.c | 2 +- arch/parisc/mm/fault.c | 2 +- arch/riscv/mm/fault.c | 2 +- arch/s390/mm/fault.c | 3 +-- arch/sparc/mm/fault_32.c | 2 +- arch/sparc/mm/fault_64.c | 2 +- arch/unicore32/mm/fault.c | 2 +- arch/xtensa/mm/fault.c | 2 +- include/linux/sched/signal.h | 15 +++++++++++++++ 18 files changed, 32 insertions(+), 18 deletions(-) diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c index 13532d244166..0bcf06f4bffc 100644 --- a/arch/alpha/mm/fault.c +++ b/arch/alpha/mm/fault.c @@ -150,7 +150,7 @@ retry: the fault. */ fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if (fault_signal_pending(fault, regs)) return; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c index 569a74b03c15..236e30a3c926 100644 --- a/arch/arm/mm/fault.c +++ b/arch/arm/mm/fault.c @@ -302,7 +302,7 @@ retry: * signal first. We do not need to release the mmap_sem because * it would already be released in __lock_page_or_retry in * mm/filemap.c. */ - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { + if (fault_signal_pending(fault, regs)) { if (!user_mode(regs)) goto no_context; return 0; diff --git a/arch/hexagon/mm/vm_fault.c b/arch/hexagon/mm/vm_fault.c index b3bc71680ae4..d19beaf11b4c 100644 --- a/arch/hexagon/mm/vm_fault.c +++ b/arch/hexagon/mm/vm_fault.c @@ -91,7 +91,7 @@ good_area: fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if (fault_signal_pending(fault, regs)) return; /* The most common case -- we are done. */ diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c index 7f8c49579a2c..de9e63737bdc 100644 --- a/arch/ia64/mm/fault.c +++ b/arch/ia64/mm/fault.c @@ -141,7 +141,7 @@ retry: */ fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if (fault_signal_pending(fault, regs)) return; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c index 03ebb67b413e..7c1eecc56382 100644 --- a/arch/m68k/mm/fault.c +++ b/arch/m68k/mm/fault.c @@ -138,7 +138,7 @@ good_area: fault = handle_mm_fault(vma, address, flags); pr_debug("handle_mm_fault returns %x\n", fault); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if (fault_signal_pending(fault, regs)) return 0; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/microblaze/mm/fault.c b/arch/microblaze/mm/fault.c index e6a810b0c7ad..cdde01dcdfc3 100644 --- a/arch/microblaze/mm/fault.c +++ b/arch/microblaze/mm/fault.c @@ -217,7 +217,7 @@ good_area: */ fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if (fault_signal_pending(fault, regs)) return; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c index f589aa8f47d9..2aeb86e5c564 100644 --- a/arch/mips/mm/fault.c +++ b/arch/mips/mm/fault.c @@ -154,7 +154,7 @@ good_area: */ fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if (fault_signal_pending(fault, regs)) return; perf_sw_event(PERF_COUNT_SW_PAGE_FAULTS, 1, regs, address); diff --git a/arch/nds32/mm/fault.c b/arch/nds32/mm/fault.c index 064ae5d2159d..c8f32b4784bd 100644 --- a/arch/nds32/mm/fault.c +++ b/arch/nds32/mm/fault.c @@ -210,7 +210,7 @@ good_area: * signal first. We do not need to release the mmap_sem because it * would already be released in __lock_page_or_retry in mm/filemap.c. */ - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { + if (fault_signal_pending(fault, regs)) { if (!user_mode(regs)) goto no_context; return; diff --git a/arch/nios2/mm/fault.c b/arch/nios2/mm/fault.c index 6a2e716b959f..704ace8ca0ee 100644 --- a/arch/nios2/mm/fault.c +++ b/arch/nios2/mm/fault.c @@ -133,7 +133,7 @@ good_area: */ fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if (fault_signal_pending(fault, regs)) return; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/openrisc/mm/fault.c b/arch/openrisc/mm/fault.c index 5d4d3a9691d0..85c7eb0c0186 100644 --- a/arch/openrisc/mm/fault.c +++ b/arch/openrisc/mm/fault.c @@ -161,7 +161,7 @@ good_area: fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if (fault_signal_pending(fault, regs)) return; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c index adbd5e2144a3..f9be1d1cb43f 100644 --- a/arch/parisc/mm/fault.c +++ b/arch/parisc/mm/fault.c @@ -304,7 +304,7 @@ good_area: fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if (fault_signal_pending(fault, regs)) return; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c index 1cfce62caa11..9c70f888bb53 100644 --- a/arch/riscv/mm/fault.c +++ b/arch/riscv/mm/fault.c @@ -117,7 +117,7 @@ good_area: * signal first. We do not need to release the mmap_sem because it * would already be released in __lock_page_or_retry in mm/filemap.c. */ - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(tsk)) + if (fault_signal_pending(fault, regs)) return; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c index 9770381776a6..bab96fd3de7c 100644 --- a/arch/s390/mm/fault.c +++ b/arch/s390/mm/fault.c @@ -482,8 +482,7 @@ retry: * the fault. */ fault = handle_mm_fault(vma, address, flags); - /* No reason to continue if interrupted by SIGKILL. */ - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) { + if (fault_signal_pending(fault, regs)) { fault = VM_FAULT_SIGNAL; if (flags & FAULT_FLAG_RETRY_NOWAIT) goto out_up; diff --git a/arch/sparc/mm/fault_32.c b/arch/sparc/mm/fault_32.c index 8d69de111470..7a62edf7f68b 100644 --- a/arch/sparc/mm/fault_32.c +++ b/arch/sparc/mm/fault_32.c @@ -237,7 +237,7 @@ good_area: */ fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if (fault_signal_pending(fault, regs)) return; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/sparc/mm/fault_64.c b/arch/sparc/mm/fault_64.c index 2371fb6b97e4..d90bafb63e17 100644 --- a/arch/sparc/mm/fault_64.c +++ b/arch/sparc/mm/fault_64.c @@ -421,7 +421,7 @@ good_area: fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if (fault_signal_pending(fault, regs)) goto exit_exception; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/arch/unicore32/mm/fault.c b/arch/unicore32/mm/fault.c index 76342de9cf8c..59d0e6ec2cfc 100644 --- a/arch/unicore32/mm/fault.c +++ b/arch/unicore32/mm/fault.c @@ -250,7 +250,7 @@ retry: * signal first. We do not need to release the mmap_sem because * it would already be released in __lock_page_or_retry in * mm/filemap.c. */ - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if (fault_signal_pending(fault, regs)) return 0; if (!(fault & VM_FAULT_ERROR) && (flags & FAULT_FLAG_ALLOW_RETRY)) { diff --git a/arch/xtensa/mm/fault.c b/arch/xtensa/mm/fault.c index f81b1478da61..8651520de460 100644 --- a/arch/xtensa/mm/fault.c +++ b/arch/xtensa/mm/fault.c @@ -110,7 +110,7 @@ good_area: */ fault = handle_mm_fault(vma, address, flags); - if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + if (fault_signal_pending(fault, regs)) return; if (unlikely(fault & VM_FAULT_ERROR)) { diff --git a/include/linux/sched/signal.h b/include/linux/sched/signal.h index 8caadcb24829..5b31804b136e 100644 --- a/include/linux/sched/signal.h +++ b/include/linux/sched/signal.h @@ -11,6 +11,8 @@ #include #include #include +#include +#include /* * Types defining task->signal and task->sighand and APIs using them: @@ -374,6 +376,19 @@ static inline int signal_pending_state(long state, struct task_struct *p) return (state & TASK_INTERRUPTIBLE) || __fatal_signal_pending(p); } +/* + * This should only be used in fault handlers to decide whether we + * should stop the current fault routine to handle the signals + * instead, especially with the case where we've got interrupted with + * a VM_FAULT_RETRY. + */ +static inline bool fault_signal_pending(vm_fault_t fault_flags, + struct pt_regs *regs) +{ + return unlikely((fault_flags & VM_FAULT_RETRY) && + fatal_signal_pending(current)); +} + /* * Reevaluate whether the task has signals pending delivery. * Wake the task if so.