Don't acquire ashmem_mutex in ashmem_shrink if we've somehow recursed into the
shrinker code from within ashmem. Just bail out, avoiding a deadlock. This is
fine, as ashmem cache pruning is advisory anyhow.
Signed-off-by: Robert Love <rlove@xxxxxxxxxx>
---
drivers/staging/android/ashmem.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/staging/android/ashmem.c b/drivers/staging/android/ashmem.c
index 634b9ae..a057cf3 100644
--- a/drivers/staging/android/ashmem.c
+++ b/drivers/staging/android/ashmem.c
@@ -363,7 +363,11 @@ static int ashmem_shrink(struct shrinker *s, struct shrink_control *sc)
if (!sc->nr_to_scan)
return lru_count;
- mutex_lock(&ashmem_mutex);
+ /* avoid recursing into this code from within ashmem itself */
+ if (!mutex_trylock(&ashmem_mutex)) {
+ return -1;
+ }
+
list_for_each_entry_safe(range, next, &ashmem_lru_list, lru) {
loff_t start = range->pgstart * PAGE_SIZE;
loff_t end = (range->pgend + 1) * PAGE_SIZE;
--
1.8.2.1
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