Messages in this thread | | | From | Nico Pache <> | Subject | [RFC 0/3] Slight improvements for OOM/Futex | Date | Thu, 21 Apr 2022 15:05:30 -0400 |
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The following 3 patches were developed while working on the OOM/Futex fix.
Patch 1: This is a nonfunctional change. The vma_is_anonymous function originally led to some confusion about what the oom reaper is checking for in __oom_reap_task_mm. This patch makes that function name more verbose.
Patch 2: Futex cleanup was designed with silent failures. Printing this failure would have led to more quickly finding the issue. This introduces a pr_info if the exit path has any issues walking the userspace list.
Patch 3: During the debug process I noticed that the oom_reap_task_mm function was always running twice for the same mm_struct; Once in the exit path and once in the oom_reaper. By checking the MMF_OOM_SKIP we can prevent these unnecissary double calls. I'd like some input from David Rientjes here with regards to CVE-2018-1000200, I want to make sure we are not reintroducing that CVE.
Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Nicholas Piggin <npiggin@gmail.com> Cc: Logan Gunthorpe <logang@deltatee.com> Cc: Hari Bathini <hbathini@linux.ibm.com> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com> Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org> Cc: Yang Shi <shy828301@gmail.com> Cc: Miaohe Lin <linmiaohe@huawei.com> Cc: William Kucharski <william.kucharski@oracle.com> Cc: Hugh Dickins <hughd@google.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Darren Hart <dvhart@infradead.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: "André Almeida" <andrealmeid@collabora.com> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Ulrich Drepper <drepper@redhat.com> Cc: Michal Hocko <mhocko@suse.com> Signed-off-by: Nico Pache <npache@redhat.com>
Nico Pache (3): mm: change vma_is_anonymous to vma_is_private_anon futex: exit: Print a warning when futex_cleanup fails exit: Check for MMF_OOM_SKIP in exit_mmap
arch/powerpc/mm/book3s64/pgtable.c | 2 +- fs/userfaultfd.c | 2 +- include/linux/huge_mm.h | 2 +- include/linux/mm.h | 2 +- kernel/futex/core.c | 44 ++++++++++++++++++------------ mm/gup.c | 4 +-- mm/huge_memory.c | 10 +++---- mm/madvise.c | 4 +-- mm/memory.c | 10 +++---- mm/migrate_device.c | 6 ++-- mm/mincore.c | 2 +- mm/mmap.c | 7 +++-- mm/oom_kill.c | 2 +- mm/userfaultfd.c | 8 +++--- 14 files changed, 57 insertions(+), 48 deletions(-)
-- 2.35.1
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