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| author | Mitchel Humpherys <mitchelh@codeaurora.org> | 2014-05-23 20:01:22 (GMT) |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-05-23 22:23:15 (GMT) |
| commit | 22f6b9789aef2e0b0b409b1d7708cc653540248c (patch) | |
| tree | d8ce2a8e49c13bffd4c240fe4619e9550b5300a4 /drivers/staging/android/ion/ion.c | |
| parent | 7949f30a36550b9feeedff10bb4b156b372c6e53 (diff) | |
| download | linux-22f6b9789aef2e0b0b409b1d7708cc653540248c.tar.xz | |
staging: ion: WARN when the handle kmap_cnt is going to wrap around
There are certain client bugs (double unmap, for example) that can cause
the handle->kmap_cnt (an unsigned int) to wrap around from zero. This
causes problems when the handle is destroyed because we have:
while (handle->kmap_cnt)
ion_handle_kmap_put(handle);
which takes a long time to complete when kmap_cnt starts at ~0 and can
result in a watchdog timeout.
WARN and bail when kmap_cnt is about to wrap around from zero.
Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org>
Acked-by: Colin Cross <ccross@android.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging/android/ion/ion.c')
| -rw-r--r-- | drivers/staging/android/ion/ion.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/drivers/staging/android/ion/ion.c b/drivers/staging/android/ion/ion.c index ea2c8a9..389b8f6 100644 --- a/drivers/staging/android/ion/ion.c +++ b/drivers/staging/android/ion/ion.c @@ -627,6 +627,10 @@ static void ion_handle_kmap_put(struct ion_handle *handle) { struct ion_buffer *buffer = handle->buffer; + if (!handle->kmap_cnt) { + WARN(1, "%s: Double unmap detected! bailing...\n", __func__); + return; + } handle->kmap_cnt--; if (!handle->kmap_cnt) ion_buffer_kmap_put(buffer); |