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Filename Latest commit message Latest commit date
Khazhismel Kumykov ee922a2f6b eventpoll: fix missing wakeup for ovflist in ep_poll_callback
commit 0c54a6a44bf3d41e76ce3f583a6ece267618df2e upstream.

In the event that we add to ovflist, before commit 339ddb53d373
("fs/epoll: remove unnecessary wakeups of nested epoll") we would be
woken up by ep_scan_ready_list, and did no wakeup in ep_poll_callback.

With that wakeup removed, if we add to ovflist here, we may never wake
up.  Rather than adding back the ep_scan_ready_list wakeup - which was
resulting in unnecessary wakeups, trigger a wake-up in ep_poll_callback.

We noticed that one of our workloads was missing wakeups starting with
339ddb53d373 and upon manual inspection, this wakeup seemed missing to me.
With this patch added, we no longer see missing wakeups.  I haven't yet
tried to make a small reproducer, but the existing kselftests in
filesystem/epoll passed for me with this patch.

[khazhy@google.com: use if/elif instead of goto + cleanup suggested by Roman]
  Link: http://lkml.kernel.org/r/20200424190039.192373-1-khazhy@google.com
Fixes: 339ddb53d373 ("fs/epoll: remove unnecessary wakeups of nested epoll")
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Roman Penyaev <rpenyaev@suse.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Roman Penyaev <rpenyaev@suse.de>
Cc: Heiher <r@hev.cc>
Cc: Jason Baron <jbaron@akamai.com>
Cc: <stable@vger.kernel.org>
Link: http://lkml.kernel.org/r/20200424025057.118641-1-khazhy@google.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-05-14 07:58:26 +02:00
arch arm64: hugetlb: avoid potential NULL dereference 2020-05-14 07:58:26 +02:00
block blk-mq: Put driver tag in blk_mq_dispatch_rq_list() when no budget 2020-05-02 08:48:59 +02:00
certs
crypto crypto: rng - Fix a refcounting bug in crypto_rng_reset() 2020-04-17 10:50:16 +02:00
Documentation USB: hub: Revert commit bd0e6c9614 ("usb: hub: try old enumeration scheme first for high speed devices") 2020-04-29 16:33:14 +02:00
drivers drm: ingenic-drm: add MODULE_DEVICE_TABLE 2020-05-14 07:58:26 +02:00
fs eventpoll: fix missing wakeup for ovflist in ep_poll_callback 2020-05-14 07:58:26 +02:00
include tunnel: Propagate ECT(1) when decapsulating as recommended by RFC6040 2020-05-14 07:58:22 +02:00
init printk: queue wake_up_klogd irq_work only if per-CPU areas are ready 2020-05-02 08:48:42 +02:00
ipc ipc/mqueue.c: change __do_notify() to bypass check_kill_permission() 2020-05-14 07:58:26 +02:00
kernel tracing: Add a vmalloc_sync_mappings() for safe measure 2020-05-14 07:58:25 +02:00
lib lib: devres: add a helper function for ioremap_uc 2020-05-10 10:31:30 +02:00
LICENSES
mm mm/mremap: Add comment explaining the untagging behaviour of mremap() 2020-05-10 10:31:33 +02:00
net sctp: Fix bundling of SHUTDOWN with COOKIE-ACK 2020-05-14 07:58:24 +02:00
samples vmalloc: fix remap_vmalloc_range() bounds checks 2020-04-29 16:33:14 +02:00
scripts scripts/config: allow colons in option strings for sed 2020-05-10 10:31:27 +02:00
security selinux: properly handle multiple messages in selinux_netlink_send() 2020-05-06 08:15:17 +02:00
sound ALSA: hda: Match both PCI ID and SSID for driver blacklist 2020-05-10 10:31:31 +02:00
tools tools headers UAPI: Sync copy of arm64's asm/unistd.h with the kernel sources 2020-05-10 10:31:33 +02:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt KVM: arm64: Fix 32bit PC wrap-around 2020-05-14 07:58:26 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: Update drm/i915 bug filing URL 2020-02-28 17:22:19 +01:00
Makefile Linux 5.4.40 2020-05-10 10:31:34 +02:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.