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authorLinus Torvalds <torvalds@linux-foundation.org>2015-01-29 10:51:32 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2015-04-29 10:34:00 +0200
commit0c42d1fbb33f7e3fc97a4854e1f9804951ebdd0d (patch)
treeb46287ec9170beb8c55c5cc15e854b9a5a399db6 /arch
parent5f03ac13d87590b0ee879c77e68df63a3d9b3e07 (diff)
downloadlinux-linaro-stable-0c42d1fbb33f7e3fc97a4854e1f9804951ebdd0d.tar.gz
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 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [shengyong: Backport to 3.10 - adjust context - ignore modification for arch nios2, because 3.10 does not support it - ignore modification for driver lustre, because 3.10 does not support it - ignore VM_FAULT_FALLBACK in VM_FAULT_ERROR, becase 3.10 does not support this flag - add SIGSEGV handling to powerpc/cell spu_fault.c, because 3.10 does not separate it to copro_fault.c - add SIGSEGV handling in mm/memory.c, because 3.10 does not separate it to gup.c ] Signed-off-by: Sheng Yong <shengyong1@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/alpha/mm/fault.c2
-rw-r--r--arch/arc/mm/fault.c2
-rw-r--r--arch/avr32/mm/fault.c2
-rw-r--r--arch/cris/mm/fault.c2
-rw-r--r--arch/frv/mm/fault.c2
-rw-r--r--arch/ia64/mm/fault.c2
-rw-r--r--arch/m32r/mm/fault.c2
-rw-r--r--arch/m68k/mm/fault.c2
-rw-r--r--arch/metag/mm/fault.c2
-rw-r--r--arch/microblaze/mm/fault.c2
-rw-r--r--arch/mips/mm/fault.c2
-rw-r--r--arch/mn10300/mm/fault.c2
-rw-r--r--arch/openrisc/mm/fault.c2
-rw-r--r--arch/parisc/mm/fault.c2
-rw-r--r--arch/powerpc/mm/fault.c2
-rw-r--r--arch/powerpc/platforms/cell/spu_fault.c2
-rw-r--r--arch/s390/mm/fault.c6
-rw-r--r--arch/score/mm/fault.c2
-rw-r--r--arch/sh/mm/fault.c2
-rw-r--r--arch/sparc/mm/fault_32.c2
-rw-r--r--arch/sparc/mm/fault_64.c2
-rw-r--r--arch/tile/mm/fault.c2
-rw-r--r--arch/um/kernel/trap.c2
-rw-r--r--arch/x86/mm/fault.c2
-rw-r--r--arch/xtensa/mm/fault.c2
25 files changed, 53 insertions, 1 deletions
diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c
index 98838a05ba6d..9d0ac091a52a 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 50533b750a99..4b70fc309c17 100644
--- a/arch/arc/mm/fault.c
+++ b/arch/arc/mm/fault.c
@@ -160,6 +160,8 @@ 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 0eca93327195..d223a8b57c1e 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 1790f22e71a2..2686a7aa8ec8 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 9a66372fc7c7..ec4917ddf678 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 7225dad87094..ba5ba7accd0d 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 e9c6a8014bd6..e3d4d4890104 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 eb1d61f68725..f0eef0491f77 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 332680e5ebf2..2de5dc695a87 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 fa4cf52aa7a6..d46a5ebb7570 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 0214a43b9911..c40a8d1c43ba 100644
--- a/arch/mips/mm/fault.c
+++ b/arch/mips/mm/fault.c
@@ -157,6 +157,8 @@ 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 3516cbdf1ee9..0c2cc5d39c8e 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 0703acf7d327..230ac20ae794 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 d10d27a720c0..c45130f56a93 100644
--- a/arch/parisc/mm/fault.c
+++ b/arch/parisc/mm/fault.c
@@ -220,6 +220,8 @@ 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 d9196c9f93d9..d51a0c110eb4 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -425,6 +425,8 @@ 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 641e7273d75a..62f3e4e48a0b 100644
--- 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 416facec4a33..d214321db727 100644
--- 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 52238983527d..6860beb2a280 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 541dc6101508..a58fec9b55e0 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 59dbd4645725..163c78712110 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 3841a081beb3..ac2db923e51a 100644
--- a/arch/sparc/mm/fault_64.c
+++ b/arch/sparc/mm/fault_64.c
@@ -443,6 +443,8 @@ 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 3ff289f422e6..12b732f593bb 100644
--- a/arch/tile/mm/fault.c
+++ b/arch/tile/mm/fault.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/um/kernel/trap.c b/arch/um/kernel/trap.c
index 5c3aef74237f..06ab0ebe0a0f 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 d8b1ff68dbb9..18bce18b2a7e 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -873,6 +873,8 @@ 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 70fa7bc42b4a..38278337d85e 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();