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authorSeth Jenkins <sethjenkins@google.com>2023-01-31 12:25:55 -0500
committerAndrew Morton <akpm@linux-foundation.org>2023-02-03 17:52:24 -0800
commit81e9d6f8647650a7bead74c5f926e29970e834d1 (patch)
tree1dd7aec15656f81754edc450d62fd3e7d218df8f /fs/aio.c
parentca2b1a5cd107d451e71e7ef463c2a2141ec078d2 (diff)
aio: fix mremap after fork null-deref
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>
Diffstat (limited to 'fs/aio.c')
-rw-r--r--fs/aio.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/fs/aio.c b/fs/aio.c
index 562916d85cba..e85ba0b77f59 100644
--- a/fs/aio.c
+++ b/fs/aio.c
@@ -361,6 +361,9 @@ static int aio_ring_mremap(struct vm_area_struct *vma)
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_area_struct *vma)
}
}
+out_unlock:
rcu_read_unlock();
spin_unlock(&mm->ioctx_lock);
return res;