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| author | Seth Jenkins <sethjenkins@google.com> | 2023-01-31 12:25:55 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-02-22 12:57:05 +0100 |
| commit | 178993157e8c50aef7f35d7d6d3b44bb428199e1 (patch) | |
| tree | 73e32f25be9fbe71f408feeeebc0c135b0390c91 | |
| parent | 3cfc5e84ac6fe3914304d4117589d113be2818f5 (diff) | |
| download | linux-178993157e8c50aef7f35d7d6d3b44bb428199e1.tar.gz linux-178993157e8c50aef7f35d7d6d3b44bb428199e1.tar.bz2 linux-178993157e8c50aef7f35d7d6d3b44bb428199e1.zip | |
aio: fix mremap after fork null-deref
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@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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | fs/aio.c | 4 |
1 files changed, 4 insertions, 0 deletions
@@ -334,6 +334,9 @@ 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; @@ -347,6 +350,7 @@ static int aio_ring_mremap(struct vm_area_struct *vma) } } +out_unlock: rcu_read_unlock(); spin_unlock(&mm->ioctx_lock); return res; |