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authorDaniel Borkmann <dborkman@redhat.com>2013-06-04 10:52:34 +0200
committerDaniel Borkmann <dborkman@redhat.com>2013-06-04 10:53:19 +0200
commit4722d3bac43062a9213a08ed2435b8ef9b426789 (patch)
treefa40f2282cda080bd697b976ae0f6ab89a38a6d4 /ring_tx.c
parent23bd5ecbd11766088784507a56e32975b4c755a2 (diff)
privs: move drop_privileges out of xutils
Again, also to be able to maintain this more easily. Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Diffstat (limited to 'ring_tx.c')
0 files changed, 0 insertions, 0 deletions
generated by cgit v1.2.3-54-g00ecf (git 2.39.0) at 2024-11-11 07:51:46 +0000
fda2d530d3b268eef542c5414e54bf1a&id2=6610d0edf6dc7ee97e46ab3a538a565c79d26199'>diff)
dmaengine: pl330: fix double lock
The static bug finder EBA (http://www.iagoabal.eu/eba/) reported the following double-lock bug: Double lock: 1. spin_lock_irqsave(pch->lock, flags) at pl330_free_chan_resources:2236; 2. call to function `pl330_release_channel' immediately after; 3. call to function `dma_pl330_rqcb' in line 1753; 4. spin_lock_irqsave(pch->lock, flags) at dma_pl330_rqcb:1505. I have fixed it as suggested by Marek Szyprowski. First, I have replaced `pch->lock' with `pl330->lock' in functions `pl330_alloc_chan_resources' and `pl330_free_chan_resources'. This avoids the double-lock by acquiring a different lock than `dma_pl330_rqcb'. NOTE that, as a result, `pl330_free_chan_resources' executes `list_splice_tail_init' on `pch->work_list' under lock `pl330->lock', whereas in the rest of the code `pch->work_list' is protected by `pch->lock'. I don't know if this may cause race conditions. Similarly `pch->cyclic' is written by `pl330_alloc_chan_resources' under `pl330->lock' but read by `pl330_tx_submit' under `pch->lock'. Second, I have removed locking from `pl330_request_channel' and `pl330_release_channel' functions. Function `pl330_request_channel' is only called from `pl330_alloc_chan_resources', so the lock is already held. Function `pl330_release_channel' is called from `pl330_free_chan_resources', which already holds the lock, and from `pl330_del'. Function `pl330_del' is called in an error path of `pl330_probe' and at the end of `pl330_remove', but I assume that there cannot be concurrent accesses to the protected data at those points. Signed-off-by: Iago Abal <mail@iagoabal.eu> Reviewed-by: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Diffstat (limited to 'tools/perf/tests/tests.h')