On Wed, 2015-03-18 at 21:14 -0700, Linus Torvalds wrote: > I hope you know that you need to backport 7fb08eca4527 too. > > Linus I do now! Queued for 3.13-stable: 7fb08ec x86: mm: move mmap_sem unlock from mm_fault_error() to caller Thanks very much, Linus. -Kamal > On Mar 18, 2015 4:26 PM, "Kamal Mostafa" <kamal@xxxxxxxxxxxxx> wrote: > This is a note to let you know that I have just added a patch > titled > > vm: add VM_FAULT_SIGSEGV handling support > > to the linux-3.13.y-queue branch of the 3.13.y-ckt extended > stable tree > which can be found at: > > http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.13.y-queue > > This patch is scheduled to be released in version > 3.13.11-ckt17. > > If you, or anyone else, feels it should not be added to this > tree, please > reply to this email. > > For more information about the 3.13.y-ckt tree, see > https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable > > Thanks. > -Kamal > > ------ > > From 8dfe997e9cb21f0f279ef819c2e05a6c2f8fdfbe Mon Sep 17 > 00:00:00 2001 > From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > Date: Thu, 29 Jan 2015 10:51:32 -0800 > Subject: vm: add VM_FAULT_SIGSEGV handling support > > commit 33692f27597fcab536d7cbbcc8f52905133e4aa7 upstream. > > The core VM already knows about VM_FAULT_SIGBUS, but cannot > return a > "you should SIGSEGV" error, because the SIGSEGV case was > generally > handled by the caller - usually the architecture fault > handler. > > That results in lots of duplication - all the architecture > fault > handlers end up doing very similar "look up vma, check > permissions, do > retries etc" - but it generally works. However, there are > cases where > the VM actually wants to SIGSEGV, and applications _expect_ > SIGSEGV. > > In particular, when accessing the stack guard page, libsigsegv > expects a > SIGSEGV. And it usually got one, because the stack growth is > handled by > that duplicated architecture fault handler. > > However, when the generic VM layer started propagating the > error return > from the stack expansion in commit fee7e49d4514 ("mm: > propagate error > from stack expansion even for guard page"), that now exposed > the > existing VM_FAULT_SIGBUS result to user space. And user space > really > expected SIGSEGV, not SIGBUS. > > To fix that case, we need to add a VM_FAULT_SIGSEGV, and teach > all those > duplicate architecture fault handlers about it. They all > already have > the code to handle SIGSEGV, so it's about just tying that new > return > value to the existing code, but it's all a bit annoying. > > This is the mindless minimal patch to do this. A more > extensive patch > would be to try to gather up the mostly shared fault handling > logic into > one generic helper routine, and long-term we really should do > that > cleanup. > > Just from this patch, you can generally see that most > architectures just > copied (directly or indirectly) the old x86 way of doing > things, but in > the meantime that original x86 model has been improved to hold > the VM > semaphore for shorter times etc and to handle VM_FAULT_RETRY > and other > "newer" things, so it would be a good idea to bring all those > improvements to the generic case and teach other architectures > about > them too. > > Reported-and-tested-by: Takashi Iwai <tiwai@xxxxxxx> > Tested-by: Jan Engelhardt <jengelh@xxxxxxx> > Acked-by: Heiko Carstens <heiko.carstens@xxxxxxxxxx> # "s390 > still compiles and boots" > Cc: linux-arch@xxxxxxxxxxxxxxx > Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> > [ kamal: omitted for 3.13-stable: > arch/nios2/mm/fault.c arch/powerpc/mm/copro_fault.c mm/gup.c > ] > Signed-off-by: Kamal Mostafa <kamal@xxxxxxxxxxxxx> > --- > arch/alpha/mm/fault.c | 2 ++ > arch/arc/mm/fault.c | 2 ++ > arch/avr32/mm/fault.c | 2 ++ > 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/metag/mm/fault.c | 2 ++ > arch/microblaze/mm/fault.c | 2 ++ > arch/mips/mm/fault.c | 2 ++ > arch/mn10300/mm/fault.c | 2 ++ > arch/openrisc/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 ++ > drivers/staging/lustre/lustre/llite/vvp_io.c | 2 +- > include/linux/mm.h | 6 ++++-- > mm/ksm.c | 2 +- > 27 files changed, 58 insertions(+), 4 deletions(-) > > diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c > index 98838a0..9d0ac09 100644 > --- a/arch/alpha/mm/fault.c > +++ b/arch/alpha/mm/fault.c > @@ -156,6 +156,8 @@ retry: > if (unlikely(fault & VM_FAULT_ERROR)) { > if (fault & VM_FAULT_OOM) > goto out_of_memory; > + else if (fault & VM_FAULT_SIGSEGV) > + goto bad_area; > else if (fault & VM_FAULT_SIGBUS) > goto do_sigbus; > BUG(); > diff --git a/arch/arc/mm/fault.c b/arch/arc/mm/fault.c > index 9c69552..15879a1 100644 > --- a/arch/arc/mm/fault.c > +++ b/arch/arc/mm/fault.c > @@ -162,6 +162,8 @@ good_area: > /* TBD: switch to pagefault_out_of_memory() */ > if (fault & VM_FAULT_OOM) > goto out_of_memory; > + else if (fault & VM_FAULT_SIGSEV) > + goto bad_area; > else if (fault & VM_FAULT_SIGBUS) > goto do_sigbus; > > diff --git a/arch/avr32/mm/fault.c b/arch/avr32/mm/fault.c > index 0eca933..d223a8b 100644 > --- a/arch/avr32/mm/fault.c > +++ b/arch/avr32/mm/fault.c > @@ -142,6 +142,8 @@ good_area: > if (unlikely(fault & VM_FAULT_ERROR)) { > if (fault & VM_FAULT_OOM) > goto out_of_memory; > + else if (fault & VM_FAULT_SIGSEGV) > + goto bad_area; > else if (fault & VM_FAULT_SIGBUS) > goto do_sigbus; > BUG(); > diff --git a/arch/cris/mm/fault.c b/arch/cris/mm/fault.c > index 1790f22..2686a7a 100644 > --- a/arch/cris/mm/fault.c > +++ b/arch/cris/mm/fault.c > @@ -176,6 +176,8 @@ retry: > if (unlikely(fault & VM_FAULT_ERROR)) { > if (fault & VM_FAULT_OOM) > goto out_of_memory; > + else if (fault & VM_FAULT_SIGSEGV) > + goto bad_area; > else if (fault & VM_FAULT_SIGBUS) > goto do_sigbus; > BUG(); > diff --git a/arch/frv/mm/fault.c b/arch/frv/mm/fault.c > index 9a66372..ec4917d 100644 > --- a/arch/frv/mm/fault.c > +++ b/arch/frv/mm/fault.c > @@ -168,6 +168,8 @@ asmlinkage void do_page_fault(int datammu, > unsigned long esr0, unsigned long ear > if (unlikely(fault & VM_FAULT_ERROR)) { > if (fault & VM_FAULT_OOM) > goto out_of_memory; > + else if (fault & VM_FAULT_SIGSEGV) > + goto bad_area; > else if (fault & VM_FAULT_SIGBUS) > goto do_sigbus; > BUG(); > diff --git a/arch/ia64/mm/fault.c b/arch/ia64/mm/fault.c > index 7225dad..ba5ba7a 100644 > --- a/arch/ia64/mm/fault.c > +++ b/arch/ia64/mm/fault.c > @@ -172,6 +172,8 @@ retry: > */ > if (fault & VM_FAULT_OOM) { > goto out_of_memory; > + } else if (fault & VM_FAULT_SIGSEGV) { > + goto bad_area; > } else if (fault & VM_FAULT_SIGBUS) { > signal = SIGBUS; > goto bad_area; > diff --git a/arch/m32r/mm/fault.c b/arch/m32r/mm/fault.c > index e9c6a80..e3d4d48901 100644 > --- a/arch/m32r/mm/fault.c > +++ b/arch/m32r/mm/fault.c > @@ -200,6 +200,8 @@ good_area: > if (unlikely(fault & VM_FAULT_ERROR)) { > if (fault & VM_FAULT_OOM) > goto out_of_memory; > + else if (fault & VM_FAULT_SIGSEGV) > + goto bad_area; > else if (fault & VM_FAULT_SIGBUS) > goto do_sigbus; > BUG(); > diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c > index eb1d61f..f0eef04 100644 > --- a/arch/m68k/mm/fault.c > +++ b/arch/m68k/mm/fault.c > @@ -153,6 +153,8 @@ good_area: > if (unlikely(fault & VM_FAULT_ERROR)) { > if (fault & VM_FAULT_OOM) > goto out_of_memory; > + else if (fault & VM_FAULT_SIGSEGV) > + goto map_err; > else if (fault & VM_FAULT_SIGBUS) > goto bus_err; > BUG(); > diff --git a/arch/metag/mm/fault.c b/arch/metag/mm/fault.c > index 332680e..2de5dc6 100644 > --- a/arch/metag/mm/fault.c > +++ b/arch/metag/mm/fault.c > @@ -141,6 +141,8 @@ good_area: > if (unlikely(fault & VM_FAULT_ERROR)) { > if (fault & VM_FAULT_OOM) > goto out_of_memory; > + else if (fault & VM_FAULT_SIGSEGV) > + goto bad_area; > else if (fault & VM_FAULT_SIGBUS) > goto do_sigbus; > BUG(); > diff --git a/arch/microblaze/mm/fault.c > b/arch/microblaze/mm/fault.c > index fa4cf52..d46a5eb 100644 > --- a/arch/microblaze/mm/fault.c > +++ b/arch/microblaze/mm/fault.c > @@ -224,6 +224,8 @@ good_area: > if (unlikely(fault & VM_FAULT_ERROR)) { > if (fault & VM_FAULT_OOM) > goto out_of_memory; > + else if (fault & VM_FAULT_SIGSEGV) > + goto bad_area; > else if (fault & VM_FAULT_SIGBUS) > goto do_sigbus; > BUG(); > diff --git a/arch/mips/mm/fault.c b/arch/mips/mm/fault.c > index becc42b..70ab5d6 100644 > --- a/arch/mips/mm/fault.c > +++ b/arch/mips/mm/fault.c > @@ -158,6 +158,8 @@ good_area: > if (unlikely(fault & VM_FAULT_ERROR)) { > if (fault & VM_FAULT_OOM) > goto out_of_memory; > + else if (fault & VM_FAULT_SIGSEGV) > + goto bad_area; > else if (fault & VM_FAULT_SIGBUS) > goto do_sigbus; > BUG(); > diff --git a/arch/mn10300/mm/fault.c b/arch/mn10300/mm/fault.c > index 3516cbd..0c2cc5d 100644 > --- a/arch/mn10300/mm/fault.c > +++ b/arch/mn10300/mm/fault.c > @@ -262,6 +262,8 @@ good_area: > if (unlikely(fault & VM_FAULT_ERROR)) { > if (fault & VM_FAULT_OOM) > goto out_of_memory; > + else if (fault & VM_FAULT_SIGSEGV) > + goto bad_area; > else if (fault & VM_FAULT_SIGBUS) > goto do_sigbus; > BUG(); > diff --git a/arch/openrisc/mm/fault.c > b/arch/openrisc/mm/fault.c > index 0703acf..230ac20 100644 > --- a/arch/openrisc/mm/fault.c > +++ b/arch/openrisc/mm/fault.c > @@ -171,6 +171,8 @@ good_area: > if (unlikely(fault & VM_FAULT_ERROR)) { > if (fault & VM_FAULT_OOM) > goto out_of_memory; > + else if (fault & VM_FAULT_SIGSEGV) > + goto bad_area; > else if (fault & VM_FAULT_SIGBUS) > goto do_sigbus; > BUG(); > diff --git a/arch/parisc/mm/fault.c b/arch/parisc/mm/fault.c > index d72197f..d27e388 100644 > --- a/arch/parisc/mm/fault.c > +++ b/arch/parisc/mm/fault.c > @@ -256,6 +256,8 @@ good_area: > */ > if (fault & VM_FAULT_OOM) > goto out_of_memory; > + else if (fault & VM_FAULT_SIGSEGV) > + goto bad_area; > else if (fault & VM_FAULT_SIGBUS) > goto bad_area; > BUG(); > diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c > index 51ab9e7..010fabf 100644 > --- a/arch/powerpc/mm/fault.c > +++ b/arch/powerpc/mm/fault.c > @@ -432,6 +432,8 @@ good_area: > */ > fault = handle_mm_fault(mm, vma, address, flags); > if (unlikely(fault & (VM_FAULT_RETRY|VM_FAULT_ERROR))) > { > + if (fault & VM_FAULT_SIGSEGV) > + goto bad_area; > rc = mm_fault_error(regs, address, fault); > if (rc >= MM_FAULT_RETURN) > goto bail; > diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c > index d95265b2..8e95432 100644 > --- a/arch/s390/mm/fault.c > +++ b/arch/s390/mm/fault.c > @@ -239,6 +239,12 @@ static noinline void > do_fault_error(struct pt_regs *regs, int fault) > do_no_context(regs); > else > pagefault_out_of_memory(); > + } else if (fault & VM_FAULT_SIGSEGV) { > + /* Kernel mode? Handle exceptions or > die */ > + if (!user_mode(regs)) > + do_no_context(regs); > + else > + do_sigsegv(regs, SEGV_MAPERR); > } else if (fault & VM_FAULT_SIGBUS) { > /* Kernel mode? Handle exceptions or > die */ > if (!user_mode(regs)) > diff --git a/arch/score/mm/fault.c b/arch/score/mm/fault.c > index 52238983..6860beb 100644 > --- a/arch/score/mm/fault.c > +++ b/arch/score/mm/fault.c > @@ -114,6 +114,8 @@ good_area: > if (unlikely(fault & VM_FAULT_ERROR)) { > if (fault & VM_FAULT_OOM) > goto out_of_memory; > + else if (fault & VM_FAULT_SIGSEGV) > + goto bad_area; > else if (fault & VM_FAULT_SIGBUS) > goto do_sigbus; > BUG(); > diff --git a/arch/sh/mm/fault.c b/arch/sh/mm/fault.c > index 541dc61..a58fec9 100644 > --- a/arch/sh/mm/fault.c > +++ b/arch/sh/mm/fault.c > @@ -353,6 +353,8 @@ mm_fault_error(struct pt_regs *regs, > unsigned long error_code, > } else { > if (fault & VM_FAULT_SIGBUS) > do_sigbus(regs, error_code, address); > + else if (fault & VM_FAULT_SIGSEGV) > + bad_area(regs, error_code, address); > else > BUG(); > } > diff --git a/arch/sparc/mm/fault_32.c > b/arch/sparc/mm/fault_32.c > index 59dbd46..163c787 100644 > --- a/arch/sparc/mm/fault_32.c > +++ b/arch/sparc/mm/fault_32.c > @@ -252,6 +252,8 @@ good_area: > if (unlikely(fault & VM_FAULT_ERROR)) { > if (fault & VM_FAULT_OOM) > goto out_of_memory; > + else if (fault & VM_FAULT_SIGSEGV) > + goto bad_area; > else if (fault & VM_FAULT_SIGBUS) > goto do_sigbus; > BUG(); > diff --git a/arch/sparc/mm/fault_64.c > b/arch/sparc/mm/fault_64.c > index 45a413e..0d6de79 100644 > --- a/arch/sparc/mm/fault_64.c > +++ b/arch/sparc/mm/fault_64.c > @@ -448,6 +448,8 @@ good_area: > if (unlikely(fault & VM_FAULT_ERROR)) { > if (fault & VM_FAULT_OOM) > goto out_of_memory; > + else if (fault & VM_FAULT_SIGSEGV) > + goto bad_area; > else if (fault & VM_FAULT_SIGBUS) > goto do_sigbus; > BUG(); > diff --git a/arch/tile/mm/fault.c b/arch/tile/mm/fault.c > index 6c05712..c6d2a76 100644 > --- a/arch/tile/mm/fault.c > +++ b/arch/tile/mm/fault.c > @@ -444,6 +444,8 @@ good_area: > if (unlikely(fault & VM_FAULT_ERROR)) { > if (fault & VM_FAULT_OOM) > goto out_of_memory; > + else if (fault & VM_FAULT_SIGSEGV) > + goto bad_area; > else if (fault & VM_FAULT_SIGBUS) > goto do_sigbus; > BUG(); > diff --git a/arch/um/kernel/trap.c b/arch/um/kernel/trap.c > index 974b874..53b8320 100644 > --- a/arch/um/kernel/trap.c > +++ b/arch/um/kernel/trap.c > @@ -80,6 +80,8 @@ good_area: > if (unlikely(fault & VM_FAULT_ERROR)) { > if (fault & VM_FAULT_OOM) { > goto out_of_memory; > + } else if (fault & VM_FAULT_SIGSEGV) { > + goto out; > } else if (fault & VM_FAULT_SIGBUS) { > err = -EACCES; > goto out; > diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c > index 6dea040..3b5a244 100644 > --- a/arch/x86/mm/fault.c > +++ b/arch/x86/mm/fault.c > @@ -894,6 +894,8 @@ mm_fault_error(struct pt_regs *regs, > unsigned long error_code, > if (fault & (VM_FAULT_SIGBUS| > VM_FAULT_HWPOISON| > VM_FAULT_HWPOISON_LARGE)) > do_sigbus(regs, error_code, address, > fault); > + else if (fault & VM_FAULT_SIGSEGV) > + bad_area_nosemaphore(regs, error_code, > address); > else > BUG(); > } > diff --git a/arch/xtensa/mm/fault.c b/arch/xtensa/mm/fault.c > index 70fa7bc..3827833 100644 > --- a/arch/xtensa/mm/fault.c > +++ b/arch/xtensa/mm/fault.c > @@ -117,6 +117,8 @@ good_area: > if (unlikely(fault & VM_FAULT_ERROR)) { > if (fault & VM_FAULT_OOM) > goto out_of_memory; > + else if (fault & VM_FAULT_SIGSEGV) > + goto bad_area; > else if (fault & VM_FAULT_SIGBUS) > goto do_sigbus; > BUG(); > diff --git a/drivers/staging/lustre/lustre/llite/vvp_io.c > b/drivers/staging/lustre/lustre/llite/vvp_io.c > index 3ff664c..37b14f3 100644 > --- a/drivers/staging/lustre/lustre/llite/vvp_io.c > +++ b/drivers/staging/lustre/lustre/llite/vvp_io.c > @@ -601,7 +601,7 @@ static int vvp_io_kernel_fault(struct > vvp_fault_io *cfio) > return 0; > } > > - if (cfio->fault.ft_flags & VM_FAULT_SIGBUS) { > + if (cfio->fault.ft_flags & (VM_FAULT_SIGBUS | > VM_FAULT_SIGSEGV)) { > CDEBUG(D_PAGE, "got addr %p - SIGBUS\n", > vmf->virtual_address); > return -EFAULT; > } > diff --git a/include/linux/mm.h b/include/linux/mm.h > index c61755d..bc205d8 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -972,6 +972,7 @@ static inline int page_mapped(struct page > *page) > #define VM_FAULT_WRITE 0x0008 /* Special case for > get_user_pages */ > #define VM_FAULT_HWPOISON 0x0010 /* Hit poisoned small > page */ > #define VM_FAULT_HWPOISON_LARGE 0x0020 /* Hit poisoned large > page. Index encoded in upper bits */ > +#define VM_FAULT_SIGSEGV 0x0040 > > #define VM_FAULT_NOPAGE 0x0100 /* ->fault installed > the pte, not return page */ > #define VM_FAULT_LOCKED 0x0200 /* ->fault locked the > returned page */ > @@ -980,8 +981,9 @@ static inline int page_mapped(struct page > *page) > > #define VM_FAULT_HWPOISON_LARGE_MASK 0xf000 /* encodes hpage > index for large hwpoison */ > > -#define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | > VM_FAULT_HWPOISON | \ > - VM_FAULT_FALLBACK | > VM_FAULT_HWPOISON_LARGE) > +#define VM_FAULT_ERROR (VM_FAULT_OOM | VM_FAULT_SIGBUS | > VM_FAULT_SIGSEGV | \ > + VM_FAULT_HWPOISON | > VM_FAULT_HWPOISON_LARGE | \ > + VM_FAULT_FALLBACK) > > /* Encode hstate index for a hwpoisoned large page */ > #define VM_FAULT_SET_HINDEX(x) ((x) << 12) > diff --git a/mm/ksm.c b/mm/ksm.c > index 418b8ca..813a1d9 100644 > --- a/mm/ksm.c > +++ b/mm/ksm.c > @@ -376,7 +376,7 @@ static int break_ksm(struct vm_area_struct > *vma, unsigned long addr) > else > ret = VM_FAULT_WRITE; > put_page(page); > - } while (!(ret & (VM_FAULT_WRITE | VM_FAULT_SIGBUS | > VM_FAULT_OOM))); > + } while (!(ret & (VM_FAULT_WRITE | VM_FAULT_SIGBUS | > VM_FAULT_SIGSEGV | VM_FAULT_OOM))); > /* > * We must loop because handle_mm_fault() may back out > if there's > * any difficulty e.g. if pte accessed bit gets > updated concurrently. > -- > 1.9.1 > -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
