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@suse.de>
Tested-by: Jan Engelhardt <jengelh@inai.de>
Acked-by: Heiko Carstens <heiko.carstens@de.ibm.com> # "s390 still compiles and boots"
Cc: linux-arch@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c
index 98838a05ba6d89f0459742131010f57c38cbed05..9d0ac091a52a7d16cf1f78f402ab48c511924a24 100644 (file)
--- 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 0c14d8a526833fd3236f680abcad6c5f63279d36..6d4094986cc4990d40ddf003cd1cbc7fca8ef7ad 100644 (file)
--- 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 0eca93327195077ec16bdfd99efd7294c6ab2de6..d223a8b57c1eaad282289e75089654153ab598d6 100644 (file)
--- 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 1790f22e71a21a859b2b7b1942cbbc503c2d557e..2686a7aa8ec82c50f29592840185b519522c53a7 100644 (file)
--- 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 9a66372fc7c76019ca874a9c3780c2fc8392266c..ec4917ddf67872aa46b60c6b067b0a67ec5417a4 100644 (file)
--- 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 7225dad87094d81e89459e5a61909fa5b2d10ca0..ba5ba7accd0d6bb4dbab34f7fc307c4306347f4a 100644 (file)
--- 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 e9c6a8014bd647eec50a66afb5bc75b076b35e4d..e3d4d4890104cc27e2eb9de2f22cb6f53f939c90 100644 (file)
--- 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 eb1d61f6872549991dae7d5e491a74627d8456d0..f0eef0491f77bbb72ed376492abc2624d2042cf1 100644 (file)
--- 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 332680e5ebf23c7909b796c415c2273efd77ba3c..2de5dc695a87fa96d41a83e127166a7126d10df0 100644 (file)
--- 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 fa4cf52aa7a6d386711690005a314ece7d67fc53..d46a5ebb7570e07869ea03b9b995374aa3bff82e 100644 (file)
--- 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 becc42bb18495adf98389bd039bc111c1893cedd..70ab5d664332694e92305331f13ed15a35ab1956 100644 (file)
--- 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 3516cbdf1ee93acb82ebef6428f79df9af104514..0c2cc5d39c8e37ce1cfe5be191902bc435c41090 100644 (file)
--- 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 0703acf7d3276811919fd3d398ada99b1b9c6d50..230ac20ae7944f71636e5083fdaf3f034eb10af2 100644 (file)
--- 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 0293588d5b8cb8e2d594406c51bbb524b319888b..0dda59ccc98dfeed4f3fb84584b2dfd3bef40c69 100644 (file)
--- a/arch/parisc/mm/fault.c
+++ b/arch/parisc/mm/fault.c
@@ -226,6 +226,8 @@ 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 51ab9e7e6c391b9497a08730a7b5e4c625c96304..010fabf3828c03757d5a063554125431222df965 100644 (file)
--- 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/powerpc/platforms/cell/spu_fault.c b/arch/powerpc/platforms/cell/spu_fault.c
index 641e7273d75ae687335716c5b4e87c9afcdb98c7..62f3e4e48a0b235a0bfe6ad577feccc8a3dc36aa 100644 (file)
--- a/arch/powerpc/platforms/cell/spu_fault.c
+++ b/arch/powerpc/platforms/cell/spu_fault.c
@@ -75,7 +75,7 @@ int spu_handle_mm_fault(struct mm_struct *mm, unsigned long ea,
                if (*flt & VM_FAULT_OOM) {
                        ret = -ENOMEM;
                        goto out_unlock;
-               } else if (*flt & VM_FAULT_SIGBUS) {
+               } else if (*flt & (VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV)) {
                        ret = -EFAULT;
                        goto out_unlock;
                }

diff --git a/arch/s390/mm/fault.c b/arch/s390/mm/fault.c
index fc6679210d83249e9b34c2f44070ab1021852e91..b53f37fbe0568d20b51e458c21ef28abd3c3f55c 100644 (file)
--- a/arch/s390/mm/fault.c
+++ b/arch/s390/mm/fault.c
@@ -244,6 +244,12 @@ 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 52238983527d605914853fd5415ea39617944ffe..6860beb2a280d0a4a65a67c89ad2201b33513068 100644 (file)
--- 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 541dc610150888e706977c7944c42ab1d61d7437..a58fec9b55e016df85cdfb7c214cc385e300479c 100644 (file)
--- 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 59dbd46457250b050ce84a48370a4f96afa3746d..163c7871211095b12d00592b0d373dd67e136d7f 100644 (file)
--- 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 603e462a210e69ab205fe68755c494513886274a..c7009d7762b1d535c041227ba92678195f139af6 100644 (file)
--- a/arch/sparc/mm/fault_64.c
+++ b/arch/sparc/mm/fault_64.c
@@ -446,6 +446,8 @@ 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 6c0571216a9d67f81a09ff331a601d22ae881566..c6d2a76d91a81e3c23d13d6bc101d88c7c3bc461 100644 (file)
--- 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 5c3aef74237ffda72a0b252d4ee4b118d14a969a..06ab0ebe0a0f39915df14044ac676ef2c9ebf546 100644 (file)
--- 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 31dceb131c46b61c80cfe476a63e2254723ac6dc..814a25d887387824c9bd1d7175cbd58f0005ec5c 100644 (file)
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -866,6 +866,8 @@ 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 70fa7bc42b4a0853012af6f6daaeb254f9c5a086..38278337d85e82690ae143fe038a9f5884eaee21 100644 (file)
--- 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 3ff664ce7503b62d22b1094d34178125b4075d26..37b14f39551e8f3448d48a7d99d6dab99f8dc6a4 100644 (file)
--- 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 306f0d4ce7e32d6f00bcada907f249061904c33d..f5965a923d4453ce5fd5f2c7c26410a0eb477259 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -886,6 +886,7 @@ 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 */
@@ -894,8 +895,9 @@ 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 29cbd06c488448b2d258641b2898ed38e42fc25f..b61ad555184f35dcddcb2965ba780337f9939d93 100644 (file)
--- 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.

diff --git a/mm/memory.c b/mm/memory.c
index cf05415c25a6b2ad6a5d8b3f380021cdd27ee485..7c11dd8b9571918089d9763c41e8cb0d5ad62f3e 100644 (file)
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1836,7 +1836,8 @@ long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
                                                else
                                                        return -EFAULT;
                                        }
-                                       if (ret & VM_FAULT_SIGBUS)
+                                       if (ret & (VM_FAULT_SIGBUS |
+                                                       VM_FAULT_SIGSEGV))
                                                return i ? i : -EFAULT;
                                        BUG();
                                }
@@ -1946,7 +1947,7 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
                        return -ENOMEM;
                if (ret & (VM_FAULT_HWPOISON | VM_FAULT_HWPOISON_LARGE))
                        return -EHWPOISON;
-               if (ret & VM_FAULT_SIGBUS)
+               if (ret & (VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV))
                        return -EFAULT;
                BUG();
        }