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>
In one of the places (ll_md_blocking_ast()) we had open-coded !is_root_inode(inode) and replaced it with is_root_inode(inode). See the last chunk of f76c23: - inode != inode->i_sb->s_root->d_inode) + is_root_inode(inode)) should've been + !is_root_inode(inode)) obviously... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* removed several pieces of dead code in lustre_compat25.h * don't open-code current_umask() (and BTW, 0755 & (S_IRWXUGO | S_ISVTX) is better spelled as 0755) * fix broken attempt to get the pathname by dentry - abusing d_path() for that is simply wrong. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull staging driver updates from Greg KH: "Here's the big staging tree pull request for 3.19-rc1. We continued to delete more lines than were added, always a good thing, but not at a huge rate this release, only about 70k lines removed overall mostly from removing the horrid bcm driver. Lots of normal staging driver cleanups and fixes all over the place, well over a thousand of them, the shortlog shows all the horrid details. The "contentious" thing here is the movement of the Android binder code out of staging into the "real" part of the kernel. This is code that has been stable for a few years now and is working as-is in the tens of millions of devices with no issues. Yes, the code is horrid, and the userspace api leaves a lot to be desired, but it's not going to change due to legacy issues that we have no control over. Because so many devices and companies rely on this, and the code is stable, might as well promote it out of staging. This was all discussed at the Linux Plumbers conference, and everyone participating agreed that this was the best way forward. There is work happening to replace the binder code with something new that is happening right now, but I don't expect to see the results of that work for another year at the earliest. If that ever happens, and Android switches over to it, I'll gladly remove this version. As for maintainers, I'll be glad to maintain this code, I've been doing it for the past few years with no problems. I'll send a MAINTAINERS entry for it before 3.19-final is out, still need to talk to the Google developers about if they are willing to help with it or not, last I checked they were, which was good. All of these patches have been in linux-next for a while with no reported issues" * tag 'staging-3.19-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging: (1382 commits) Staging: slicoss: Fix long line issues in slicoss.c staging: rtl8712: remove unnecessary else after return staging: comedi: change some printk calls to pr_err staging: rtl8723au: hal: Removed the extra semicolon lustre: Deletion of unnecessary checks before three function calls staging: lustre: fix sparse warnings: static function declaration staging: lustre: fixed sparse warnings related to static declarations staging: unisys: remove duplicate header staging: unisys: remove unneeded structure staging: ft1000 : replace __attribute ((__packed__) with __packed drivers: staging: rtl8192e: Include "asm/unaligned.h" instead of "access_ok.h" in "rtl819x_BAProc.c" Drivers:staging:rtl8192e: Fixed checkpatch warning Drivers:staging:clocking-wizard: Added a newline staging: clocking-wizard: check for a valid clk_name pointer staging: rtl8723au: Hal_InitPGData() avoid unnecessary typecasts staging: rtl8723au: _DisableAnalog(): Avoid zero-init variables unnecessarily staging: rtl8723au: Remove unnecessary wrapper _ResetDigitalProcedure1() staging: rtl8723au: _ResetDigitalProcedure1_92C() reduce code obfuscation staging: rtl8723au: Remove unnecessary wrapper _DisableRFAFEAndResetBB() staging: rtl8723au: _DisableRFAFEAndResetBB8192C(): Reduce code obfuscation ...
The functions free_ll_remote_perm(), free_rmtperm_hash() and iput() test whether their argument is NULL and then return immediately. Thus the test around their calls is not needed. This issue was detected by using the Coccinelle software. Signed-off-by: Markus Elfring <elfring@users.sourceforge.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Vincenzo Scotti <vinc94@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
drivers/staging/lustre/lustre/mdc/mdc_request.c:63:5: warning: symbol 'mdc_unpack_capa' was not declared. Should it be static? drivers/staging/lustre/lustre/mdc/mdc_request.c:150:5: warning: symbol 'mdc_getstatus' was not declared. Should it be static? drivers/staging/lustre/lustre/mdc/mdc_request.c:217:5: warning: symbol 'mdc_getattr' was not declared. Should it be static? drivers/staging/lustre/lustre/mdc/mdc_request.c:261:5: warning: symbol 'mdc_getattr_name' was not declared. Should it be static? drivers/staging/lustre/lustre/mdc/mdc_request.c:444:5: warning: symbol 'mdc_setxattr' was not declared. Should it be static? drivers/staging/lustre/lustre/mdc/mdc_request.c:455:5: warning: symbol 'mdc_getxattr' was not declared. Should it be static? Signed-off-by: Janet Liu <jianhua.ljh@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
checkpatch complains about two places where a space is prohibited before the braces for in "#if defined()" check. This patch removes these warnings. Signed-off-by: Andreas Ruprecht <rupran@einserver.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
checkpatch complains about three places where braces are not necessary. This patch removes the braces. Signed-off-by: Andreas Ruprecht <rupran@einserver.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
checkpatch finds two unnecessary line continuations in ldlm_lockd.c which are removed by this patch. Signed-off-by: Andreas Ruprecht <rupran@einserver.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>