From: Christoph Rohland <cr@sap.com>
To: "Stephen C. Tweedie" <sct@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Linus Torvalds <torvalds@transmeta.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Ben LaHaise <bcrl@redhat.com>
Subject: Re: [PATCH] Fix races in 2.4.2-ac22 SysV shared memory
Date: 28 Mar 2001 11:18:16 +0200 [thread overview]
Message-ID: <m3g0fz3qd0.fsf@linux.local> (raw)
In-Reply-To: 20010323011331.J7756@redhat.com
Hi Stephen,
On Fri, 23 Mar 2001, Stephen C. Tweedie wrote:
> @@ -234,11 +243,11 @@
> return -ENOMEM;
> }
>
> - spin_lock(&info->lock);
> - shmem_recalc_inode(page->mapping->host);
> entry = shmem_swp_entry(info, page->index);
> if (IS_ERR(entry)) /* this had been allocted on page allocation */
> BUG();
> + spin_lock(&info->lock);
> + shmem_recalc_inode(page->mapping->host);
> error = -EAGAIN;
> if (entry->val) {
> __swap_free(swap, 2);
I think this is wrong. The spinlock protects us against
shmem_truncate. shmem_swp_entry cannot sleep in this case since the
entry is allocated in nopage.
Greetings
Christoph
WARNING: multiple messages have this Message-ID (diff)
From: Christoph Rohland <cr@sap.com>
To: "Stephen C. Tweedie" <sct@redhat.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Linus Torvalds <torvalds@transmeta.com>,
Alan Cox <alan@lxorguk.ukuu.org.uk>,
Ben LaHaise <bcrl@redhat.com>
Subject: Re: [PATCH] Fix races in 2.4.2-ac22 SysV shared memory
Date: 28 Mar 2001 11:18:16 +0200 [thread overview]
Message-ID: <m3g0fz3qd0.fsf@linux.local> (raw)
In-Reply-To: 20010323011331.J7756@redhat.com
Hi Stephen,
On Fri, 23 Mar 2001, Stephen C. Tweedie wrote:
> @@ -234,11 +243,11 @@
> return -ENOMEM;
> }
>
> - spin_lock(&info->lock);
> - shmem_recalc_inode(page->mapping->host);
> entry = shmem_swp_entry(info, page->index);
> if (IS_ERR(entry)) /* this had been allocted on page allocation */
> BUG();
> + spin_lock(&info->lock);
> + shmem_recalc_inode(page->mapping->host);
> error = -EAGAIN;
> if (entry->val) {
> __swap_free(swap, 2);
I think this is wrong. The spinlock protects us against
shmem_truncate. shmem_swp_entry cannot sleep in this case since the
entry is allocated in nopage.
Greetings
Christoph
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next prev parent reply other threads:[~2001-03-28 9:22 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-03-23 1:13 [PATCH] Fix races in 2.4.2-ac22 SysV shared memory Stephen C. Tweedie
2001-03-23 19:58 ` Linus Torvalds
2001-03-23 19:58 ` Linus Torvalds
2001-03-23 22:20 ` Alan Cox
2001-03-23 22:20 ` Alan Cox
2001-03-23 22:23 ` Alexander Viro
2001-03-23 22:23 ` Alexander Viro
2001-03-23 22:29 ` Alan Cox
2001-03-23 22:29 ` Alan Cox
2001-03-23 22:27 ` Linus Torvalds
2001-03-23 22:27 ` Linus Torvalds
2001-03-23 22:35 ` Alan Cox
2001-03-23 22:35 ` Alan Cox
2001-03-23 22:37 ` Linus Torvalds
2001-03-23 22:37 ` Linus Torvalds
2001-03-23 22:31 ` David S. Miller
2001-03-23 22:31 ` David S. Miller
2001-03-25 0:13 ` Stephen C. Tweedie
2001-03-25 0:13 ` Stephen C. Tweedie
2001-03-25 1:05 ` Rik van Riel
2001-03-25 1:05 ` Rik van Riel
2001-03-25 16:50 ` Stephen C. Tweedie
2001-03-25 16:50 ` Stephen C. Tweedie
2001-03-28 9:18 ` Christoph Rohland [this message]
2001-03-28 9:18 ` Christoph Rohland
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