diff options
| author | Riley Andrews <riandrews@android.com> | 2015-11-09 13:16:32 -0800 |
|---|---|---|
| committer | John Stultz <john.stultz@linaro.org> | 2016-02-16 13:54:24 -0800 |
| commit | aa29c32d396b6e7cf9192e607760fa1d6a56cc21 (patch) | |
| tree | 3d09aaa082df6d9e71a7bc11b609a0351abe9704 /drivers/android | |
| parent | 52354e599db683dad784f3d353ffe45bc248e2ec (diff) | |
android: drivers: workaround debugfs race in binder
If a /d/binder/proc/[pid] entry is kept open after linux has
torn down the associated process, binder_proc_show can deference
an invalid binder_proc that has been stashed in the debugfs
inode. Validate that the binder_proc ptr passed into binder_proc_show
has not been freed by looking for it within the global process list
whilst the global lock is held. If the ptr is not valid, print nothing.
Bug: 19587483
Change-Id: Idd5ad79f5648b7eed49d1ec75ae93f9e12a74ee9
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
Diffstat (limited to 'drivers/android')
| -rw-r--r-- | drivers/android/binder.c | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/drivers/android/binder.c b/drivers/android/binder.c index 1db376184955..f0ce9959d14d 100644 --- a/drivers/android/binder.c +++ b/drivers/android/binder.c @@ -3600,13 +3600,24 @@ static int binder_transactions_show(struct seq_file *m, void *unused) static int binder_proc_show(struct seq_file *m, void *unused) { + struct binder_proc *itr; struct binder_proc *proc = m->private; int do_lock = !binder_debug_no_lock; + bool valid_proc = false; if (do_lock) binder_lock(__func__); - seq_puts(m, "binder proc state:\n"); - print_binder_proc(m, proc, 1); + + hlist_for_each_entry(itr, &binder_procs, proc_node) { + if (itr == proc) { + valid_proc = true; + break; + } + } + if (valid_proc) { + seq_puts(m, "binder proc state:\n"); + print_binder_proc(m, proc, 1); + } if (do_lock) binder_unlock(__func__); return 0; |