From: Michal Hocko <mhocko@kernel.org> To: <linux-mm@kvack.org>, Andrew Morton <akpm@linux-foundation.org> Cc: LKML <linux-kernel@vger.kernel.org>, Michal Hocko <mhocko@suse.com>, Oleg Nesterov <oleg@redhat.com>, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, Konstantin Khlebnikov <koct9i@gmail.com>, Andrea Arcangeli <aarcange@redhat.com>, Alexander Viro <viro@zeniv.linux.org.uk> Subject: [PATCH 03/18] mm: make vm_munmap killable Date: Tue, 26 Apr 2016 14:56:10 +0200 [thread overview] Message-ID: <1461675385-5934-4-git-send-email-mhocko@kernel.org> (raw) In-Reply-To: <1461675385-5934-1-git-send-email-mhocko@kernel.org> From: Michal Hocko <mhocko@suse.com> Almost all current users of vm_munmap are ignoring the return value and so they do not handle potential error. This means that some VMAs might stay behind. This patch doesn't try to solve those potential problems. Quite contrary it adds a new failure mode by using down_write_killable in vm_munmap. This should be safer than other failure modes, though, because the process is guaranteed to die as soon as it leaves the kernel and exit_mmap will clean the whole address space. This will help in the OOM conditions when the oom victim might be stuck waiting for the mmap_sem for write which in turn can block oom_reaper which relies on the mmap_sem for read to make a forward progress and reclaim the address space of the victim. Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Michal Hocko <mhocko@suse.com> --- mm/mmap.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index 1d229487dab1..032605bda665 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2494,11 +2494,9 @@ int vm_munmap(unsigned long start, size_t len) int ret; struct mm_struct *mm = current->mm; - /* - * XXX convert to down_write_killable as soon as all users are able - * to handle the error. - */ - down_write(&mm->mmap_sem); + if (down_write_killable(&mm->mmap_sem)) + return -EINTR; + ret = do_munmap(mm, start, len); up_write(&mm->mmap_sem); return ret; -- 2.8.0.rc3
WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@kernel.org> To: linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org> Cc: LKML <linux-kernel@vger.kernel.org>, Michal Hocko <mhocko@suse.com>, Oleg Nesterov <oleg@redhat.com>, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, Konstantin Khlebnikov <koct9i@gmail.com>, Andrea Arcangeli <aarcange@redhat.com>, Alexander Viro <viro@zeniv.linux.org.uk> Subject: [PATCH 03/18] mm: make vm_munmap killable Date: Tue, 26 Apr 2016 14:56:10 +0200 [thread overview] Message-ID: <1461675385-5934-4-git-send-email-mhocko@kernel.org> (raw) In-Reply-To: <1461675385-5934-1-git-send-email-mhocko@kernel.org> From: Michal Hocko <mhocko@suse.com> Almost all current users of vm_munmap are ignoring the return value and so they do not handle potential error. This means that some VMAs might stay behind. This patch doesn't try to solve those potential problems. Quite contrary it adds a new failure mode by using down_write_killable in vm_munmap. This should be safer than other failure modes, though, because the process is guaranteed to die as soon as it leaves the kernel and exit_mmap will clean the whole address space. This will help in the OOM conditions when the oom victim might be stuck waiting for the mmap_sem for write which in turn can block oom_reaper which relies on the mmap_sem for read to make a forward progress and reclaim the address space of the victim. Cc: Oleg Nesterov <oleg@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Signed-off-by: Michal Hocko <mhocko@suse.com> --- mm/mmap.c | 8 +++----- 1 file changed, 3 insertions(+), 5 deletions(-) diff --git a/mm/mmap.c b/mm/mmap.c index 1d229487dab1..032605bda665 100644 --- a/mm/mmap.c +++ b/mm/mmap.c @@ -2494,11 +2494,9 @@ int vm_munmap(unsigned long start, size_t len) int ret; struct mm_struct *mm = current->mm; - /* - * XXX convert to down_write_killable as soon as all users are able - * to handle the error. - */ - down_write(&mm->mmap_sem); + if (down_write_killable(&mm->mmap_sem)) + return -EINTR; + ret = do_munmap(mm, start, len); up_write(&mm->mmap_sem); return ret; -- 2.8.0.rc3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2016-04-26 12:56 UTC|newest] Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-04-26 12:56 [PATCH 0/18] change mmap_sem taken for write killable v2 Michal Hocko 2016-04-26 12:56 ` Michal Hocko 2016-04-26 12:56 ` [PATCH 01/18] mm: Make mmap_sem for write waits killable for mm syscalls Michal Hocko 2016-04-26 12:56 ` Michal Hocko 2016-04-26 12:56 ` [PATCH 02/18] mm: make vm_mmap killable Michal Hocko 2016-04-26 12:56 ` Michal Hocko 2016-04-26 12:56 ` Michal Hocko [this message] 2016-04-26 12:56 ` [PATCH 03/18] mm: make vm_munmap killable Michal Hocko 2016-04-26 12:56 ` [PATCH 04/18] mm, aout: handle vm_brk failures Michal Hocko 2016-04-26 12:56 ` Michal Hocko 2016-04-26 12:56 ` [PATCH 05/18] mm, elf: handle vm_brk error Michal Hocko 2016-04-26 12:56 ` Michal Hocko 2016-04-26 12:56 ` [PATCH 06/18] mm: make vm_brk killable Michal Hocko 2016-04-26 12:56 ` Michal Hocko 2016-04-26 12:56 ` [PATCH 07/18] mm, proc: make clear_refs killable Michal Hocko 2016-04-26 12:56 ` Michal Hocko 2016-04-26 12:56 ` [PATCH 08/18] mm, fork: make dup_mmap wait for mmap_sem for write killable Michal Hocko 2016-04-26 12:56 ` Michal Hocko 2016-04-26 12:56 ` [PATCH 09/18] ipc, shm: make shmem attach/detach wait for mmap_sem killable Michal Hocko 2016-04-26 12:56 ` Michal Hocko 2016-04-26 12:56 ` [PATCH 10/18] vdso: make arch_setup_additional_pages wait for mmap_sem for write killable Michal Hocko 2016-04-26 12:56 ` Michal Hocko 2016-04-26 12:56 ` Michal Hocko 2016-04-26 12:56 ` [PATCH 11/18] coredump: make coredump_wait " Michal Hocko 2016-04-26 12:56 ` Michal Hocko 2016-04-26 12:56 ` [PATCH 12/18] aio: make aio_setup_ring killable Michal Hocko 2016-04-26 12:56 ` Michal Hocko 2016-04-26 12:56 ` [PATCH 13/18] exec: make exec path waiting for mmap_sem killable Michal Hocko 2016-04-26 12:56 ` Michal Hocko 2016-04-26 12:56 ` [PATCH 14/18] prctl: make PR_SET_THP_DISABLE wait " Michal Hocko 2016-04-26 12:56 ` Michal Hocko 2016-04-26 15:18 ` Alex Thorlton 2016-04-26 15:18 ` Alex Thorlton 2016-04-26 12:56 ` [PATCH 15/18] uprobes: wait for mmap_sem for write killable Michal Hocko 2016-04-26 12:56 ` Michal Hocko 2016-04-26 12:56 ` [PATCH 16/18] drm/i915: make i915_gem_mmap_ioctl wait for mmap_sem killable Michal Hocko 2016-04-26 12:56 ` Michal Hocko 2016-04-26 12:56 ` [PATCH 17/18] drm/radeon: make radeon_mn_get " Michal Hocko 2016-04-26 12:56 ` Michal Hocko 2016-04-26 12:56 ` [PATCH 18/18] drm/amdgpu: make amdgpu_mn_get " Michal Hocko 2016-04-26 12:56 ` Michal Hocko -- strict thread matches above, loose matches on Subject: below -- 2016-02-29 13:26 [PATCH 0/18] change mmap_sem taken for write killable Michal Hocko 2016-02-29 13:26 ` [PATCH 03/18] mm: make vm_munmap killable Michal Hocko 2016-02-29 13:26 ` Michal Hocko 2016-02-29 13:26 ` Michal Hocko 2016-03-11 10:06 ` Vlastimil Babka 2016-03-11 10:06 ` Vlastimil Babka 2016-03-11 10:06 ` Vlastimil Babka 2016-03-11 12:32 ` Michal Hocko 2016-03-11 12:32 ` Michal Hocko 2016-03-11 12:32 ` Michal Hocko
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=1461675385-5934-4-git-send-email-mhocko@kernel.org \ --to=mhocko@kernel.org \ --cc=aarcange@redhat.com \ --cc=akpm@linux-foundation.org \ --cc=kirill.shutemov@linux.intel.com \ --cc=koct9i@gmail.com \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-mm@kvack.org \ --cc=mhocko@suse.com \ --cc=oleg@redhat.com \ --cc=viro@zeniv.linux.org.uk \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.