This is a note to let you know that I've just added the patch titled
aio: fix mremap after fork null-deref
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
aio-fix-mremap-after-fork-null-deref.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 81e9d6f8647650a7bead74c5f926e29970e834d1 Mon Sep 17 00:00:00 2001
From: Seth Jenkins <sethjenkins@xxxxxxxxxx>
Date: Tue, 31 Jan 2023 12:25:55 -0500
Subject: aio: fix mremap after fork null-deref
From: Seth Jenkins <sethjenkins@xxxxxxxxxx>
commit 81e9d6f8647650a7bead74c5f926e29970e834d1 upstream.
Commit e4a0d3e720e7 ("aio: Make it possible to remap aio ring") introduced
a null-deref if mremap is called on an old aio mapping after fork as
mm->ioctx_table will be set to NULL.
[jmoyer@xxxxxxxxxx: fix 80 column issue]
Link: https://lkml.kernel.org/r/x49sffq4nvg.fsf@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: e4a0d3e720e7 ("aio: Make it possible to remap aio ring")
Signed-off-by: Seth Jenkins <sethjenkins@xxxxxxxxxx>
Signed-off-by: Jeff Moyer <jmoyer@xxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Benjamin LaHaise <bcrl@xxxxxxxxx>
Cc: Jann Horn <jannh@xxxxxxxxxx>
Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
fs/aio.c | 4 ++++
1 file changed, 4 insertions(+)
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -334,6 +334,9 @@ static int aio_ring_mremap(struct vm_are
spin_lock(&mm->ioctx_lock);
rcu_read_lock();
table = rcu_dereference(mm->ioctx_table);
+ if (!table)
+ goto out_unlock;
+
for (i = 0; i < table->nr; i++) {
struct kioctx *ctx;
@@ -347,6 +350,7 @@ static int aio_ring_mremap(struct vm_are
}
}
+out_unlock:
rcu_read_unlock();
spin_unlock(&mm->ioctx_lock);
return res;
Patches currently in stable-queue which might be from sethjenkins@xxxxxxxxxx are
queue-5.15/aio-fix-mremap-after-fork-null-deref.patch
