From: David Howells <dhowells@redhat.com>
To: torvalds@linux-foundation.org
Cc: dhowells@redhat.com, Casey Schaufler <casey@schaufler-ca.com>,
Stephen Smalley <sds@tycho.nsa.gov>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
nicolas.dichtel@6wind.com, raven@themaw.net,
Christian Brauner <christian@brauner.io>,
dhowells@redhat.com, keyrings@vger.kernel.org,
linux-usb@vger.kernel.org, linux-block@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [RFC PATCH 08/21] pipe: Check for ring full inside of the spinlock in pipe_write()
Date: Tue, 15 Oct 2019 22:49:01 +0100 [thread overview]
Message-ID: <157117614109.15019.15677943675625422728.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <157117606853.15019.15459271147790470307.stgit@warthog.procyon.org.uk>
Make pipe_write() check to see if the ring has become full between it
taking the pipe mutex, checking the ring status and then taking the
spinlock.
This can happen if a notification is written into the pipe as that happens
without the pipe mutex.
Signed-off-by: David Howells <dhowells@redhat.com>
---
fs/pipe.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/fs/pipe.c b/fs/pipe.c
index 289a887f6b5b..0255a5ca5097 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -462,6 +462,11 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
spin_lock_irq(&pipe->wait.lock);
head = pipe->head;
+ if (head - pipe->tail == buffers) {
+ spin_unlock_irq(&pipe->wait.lock);
+ continue;
+ }
+
pipe_commit_write(pipe, head + 1);
/* Always wake up, even if the copy fails. Otherwise
next prev parent reply other threads:[~2019-10-15 21:49 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-15 21:47 [RFC PATCH 00/21] pipe: Keyrings, Block and USB notifications David Howells
2019-10-15 21:47 ` [RFC PATCH 01/21] pipe: Reduce #inclusion of pipe_fs_i.h David Howells
2019-10-15 21:48 ` [RFC PATCH 02/21] Add a prelocked wake-up David Howells
2019-10-15 22:14 ` Linus Torvalds
2019-10-16 17:02 ` Tim Chen
2019-10-15 22:33 ` David Howells
2019-10-16 14:26 ` David Howells
2019-10-16 15:31 ` Linus Torvalds
2019-10-15 21:48 ` [RFC PATCH 03/21] pipe: Use head and tail pointers for the ring, not cursor and length David Howells
2019-10-16 7:46 ` Rasmus Villemoes
2019-10-17 10:53 ` David Howells
2019-10-15 21:48 ` [RFC PATCH 04/21] pipe: Advance tail pointer inside of wait spinlock in pipe_read() David Howells
2019-10-15 21:48 ` [RFC PATCH 05/21] pipe: Conditionalise wakeup " David Howells
2019-10-15 21:48 ` [RFC PATCH 06/21] pipe: Rearrange sequence in pipe_write() to preallocate slot David Howells
2019-10-15 21:48 ` [RFC PATCH 07/21] pipe: Remove redundant wakeup from pipe_write() David Howells
2019-10-15 21:49 ` David Howells [this message]
2019-10-15 22:20 ` [RFC PATCH 08/21] pipe: Check for ring full inside of the spinlock in pipe_write() Linus Torvalds
2019-10-15 21:49 ` [RFC PATCH 09/21] uapi: General notification queue definitions David Howells
2019-10-15 21:49 ` [RFC PATCH 10/21] security: Add hooks to rule on setting a watch David Howells
2019-10-15 21:49 ` [RFC PATCH 11/21] security: Add a hook for the point of notification insertion David Howells
2019-10-15 21:49 ` [RFC PATCH 12/21] pipe: Add general notification queue support David Howells
2019-10-15 21:49 ` [RFC PATCH 13/21] keys: Add a notification facility David Howells
2019-10-15 21:49 ` [RFC PATCH 14/21] Add sample notification program David Howells
2019-10-15 21:50 ` [RFC PATCH 15/21] pipe: Allow buffers to be marked read-whole-or-error for notifications David Howells
2019-10-15 21:50 ` [RFC PATCH 16/21] pipe: Add notification lossage handling David Howells
2019-10-15 21:50 ` [RFC PATCH 17/21] Add a general, global device notification watch list David Howells
2019-10-15 21:50 ` [RFC PATCH 18/21] block: Add block layer notifications David Howells
2019-10-15 21:50 ` [RFC PATCH 19/21] usb: Add USB subsystem notifications David Howells
2019-10-15 21:50 ` [RFC PATCH 20/21] selinux: Implement the watch_key security hook David Howells
2019-10-15 21:50 ` [RFC PATCH 21/21] smack: Implement the watch_key and post_notification hooks David Howells
2019-10-15 22:11 ` [RFC PATCH 00/21] pipe: Keyrings, Block and USB notifications James Morris
2019-10-15 22:32 ` Linus Torvalds
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