Joel Fernandes cb57469c95 staging: android: ashmem: Fix lockdep issue during llseek ... ashmem_mutex create a chain of dependencies like so: (1) mmap syscall -> mmap_sem -> (acquired) ashmem_mmap ashmem_mutex (try to acquire) (block) (2) llseek syscall -> ashmem_llseek -> ashmem_mutex -> (acquired) inode_lock -> inode->i_rwsem (try to acquire) (block) (3) getdents -> iterate_dir -> inode_lock -> inode->i_rwsem (acquired) copy_to_user -> mmap_sem (try to acquire) There is a lock ordering created between mmap_sem and inode->i_rwsem causing a lockdep splat [2] during a syzcaller test, this patch fixes the issue by unlocking the mutex earlier. Functionally that's Ok since we don't need to protect vfs_llseek. [1] https://patchwork.kernel.org/patch/10185031/ [2] https://lkml.org/lkml/2018/1/10/48 Acked-by: Todd Kjos <tkjos@google.com> Cc: Arve Hjonnevag <arve@android.com> Cc: stable@vger.kernel.org Reported-by: syzbot+8ec30bb7bf1a981a2012@syzkaller.appspotmail.com Signed-off-by: Joel Fernandes <joelaf@google.com> Acked-by: Greg Hackmann <ghackmann@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2018-03-01 17:37:07 +01:00
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ion	staging: android: ion: Zero CMA allocated memory	2018-02-16 17:50:09 +01:00
uapi	staging: android: Remove redundant license text	2017-11-28 13:20:48 +01:00
ashmem.c	staging: android: ashmem: Fix lockdep issue during llseek	2018-03-01 17:37:07 +01:00
ashmem.h	staging: android: add SPDX identifiers to all android driver files	2017-11-28 13:20:47 +01:00
Kconfig
Makefile
TODO	staging: android: TODO: Removing an invalid issue	2017-10-03 18:36:57 +02:00