The patch titled Subject: aio: fix mremap after fork null-deref has been added to the -mm mm-hotfixes-unstable branch. Its filename is aio-fix-mremap-after-fork-null-deref.patch

This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches...

This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------ From: Seth Jenkins sethjenkins@google.com Subject: aio: fix mremap after fork null-deref Date: Tue, 31 Jan 2023 12:25:55 -0500

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@redhat.com: fix 80 column issue] Link: https://lkml.kernel.org/r/x49sffq4nvg.fsf@segfault.boston.devel.redhat.com Fixes: e4a0d3e720e7 ("aio: Make it possible to remap aio ring") Signed-off-by: Seth Jenkins sethjenkins@google.com Signed-off-by: Jeff Moyer jmoyer@redhat.com Cc: Alexander Viro viro@zeniv.linux.org.uk Cc: Benjamin LaHaise bcrl@kvack.org Cc: Jann Horn jannh@google.com Cc: Pavel Emelyanov xemul@parallels.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

fs/aio.c | 4 ++++ 1 file changed, 4 insertions(+)

--- a/fs/aio.c~aio-fix-mremap-after-fork-null-deref +++ a/fs/aio.c @@ -361,6 +361,9 @@ 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;

@@ -374,6 +377,7 @@ static int aio_ring_mremap(struct vm_are } }

+out_unlock: rcu_read_unlock(); spin_unlock(&mm->ioctx_lock); return res; _

Patches currently in -mm which might be from sethjenkins@google.com are

aio-fix-mremap-after-fork-null-deref.patch