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Filename Latest commit message Latest commit date
Oleg Nesterov df19e2d7bd poll_wait: add mb() to fix theoretical race between waitqueue_active() and .poll()
[ Upstream commit cacd9ae4bf801ff4125d8961bb9a3ba955e51680 ]

As the comment above waitqueue_active() explains, it can only be used
if both waker and waiter have mb()'s that pair with each other. However
__pollwait() is broken in this respect.

This is not pipe-specific, but let's look at pipe_poll() for example:

	poll_wait(...); // -> __pollwait() -> add_wait_queue()

	LOAD(pipe->head);
	LOAD(pipe->head);

In theory these LOAD()'s can leak into the critical section inside
add_wait_queue() and can happen before list_add(entry, wq_head), in this
case pipe_poll() can race with wakeup_pipe_readers/writers which do

	smp_mb();
	if (waitqueue_active(wq_head))
		wake_up_interruptible(wq_head);

There are more __pollwait()-like functions (grep init_poll_funcptr), and
it seems that at least ep_ptable_queue_proc() has the same problem, so the
patch adds smp_mb() into poll_wait().

Link: https://lore.kernel.org/all/20250102163320.GA17691@redhat.com/
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Link: https://lore.kernel.org/r/20250107162717.GA18922@redhat.com
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-02-01 18:18:51 +01:00
arch arm64: dts: rockchip: add hevc power domain clock to rk3328 2025-02-01 18:18:49 +01:00
block blk-iocost: Avoid using clamp() on inuse in __propagate_weights() 2024-12-19 18:05:04 +01:00
certs
crypto
Documentation PCI: Add 'reset_subordinate' to reset hierarchy below bridge 2024-12-14 19:44:54 +01:00
drivers i2c: mux: demux-pinctrl: check initial mux selection, too 2025-02-01 18:18:50 +01:00
fs hfs: Sanity check the root record 2025-02-01 18:18:50 +01:00
include poll_wait: add mb() to fix theoretical race between waitqueue_active() and .poll() 2025-02-01 18:18:51 +01:00
init
ipc
kernel kheaders: Ignore silly-rename files 2025-02-01 18:18:51 +01:00
lib
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mm mm: vmscan: account for free pages to prevent infinite Loop in throttle_direct_reclaim() 2025-01-09 13:23:37 +01:00
net mac802154: check local interfaces before deleting sdata list 2025-02-01 18:18:50 +01:00
samples samples/bpf: Fix a resource leak 2024-12-14 19:44:50 +01:00
scripts modpost: fix the missed iteration for the max bit in do_input() 2025-01-09 13:23:36 +01:00
security selinux: ignore unknown extended permissions 2025-01-09 13:23:33 +01:00
sound sound: usb: format: don't warn that raw DSD is unsupported 2025-01-09 13:23:36 +01:00
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virt KVM: arm64: Ignore PMCNTENSET_EL0 while checking for overflow status 2024-12-19 18:05:04 +01:00
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Makefile Linux 5.4.289 2025-01-09 13:23:37 +01:00
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.