[3.13.y-ckt stable] Patch "vm: add VM_FAULT_SIGSEGV handling support" has been added to staging queue
Kamal Mostafa
kamal at canonical.com
Thu Mar 19 17:49:07 UTC 2015
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 at canonical.com> 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 at linux-foundation.org>
> 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 at suse.de>
> Tested-by: Jan Engelhardt <jengelh at inai.de>
> Acked-by: Heiko Carstens <heiko.carstens at de.ibm.com> # "s390
> still compiles and boots"
> Cc: linux-arch at vger.kernel.org
> Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
> [ 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 at canonical.com>
> ---
> 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
>
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