#include #include #include #include #define NODES 100 #define PERF_LOOPS 100000 #define SEARCHES 100 #define SEARCH_LOOPS 10000 static struct rb_root root = RB_ROOT; static struct interval_tree_node nodes[NODES]; static u32 queries[SEARCHES]; static struct rnd_state rnd; static inline unsigned long search(unsigned long query, struct rb_root *root) { struct interval_tree_node *node; unsigned long results = 0; for (node = interval_tree_iter_first(root, query, query); node; node = interval_tree_iter_next(node, query, query)) results++; return results; } static void init(void) { int i; for (i = 0; i < NODES; i++) { u32 a = prandom_u32_state(&rnd); u32 b = prandom_u32_state(&rnd); if (a <= b) { nodes[i].start = a; nodes[i].last = b; } else { nodes[i].start = b; nodes[i].last = a; } } for (i = 0; i < SEARCHES; i++) queries[i] = prandom_u32_state(&rnd); } static int interval_tree_test_init(void) { int i, j; unsigned long results; cycles_t time1, time2, time; printk(KERN_ALERT "interval tree insert/remove"); prandom_seed_state(&rnd, 3141592653589793238ULL); init(); time1 = get_cycles(); for (i = 0; i < PERF_LOOPS; i++) { for (j = 0; j < NODES; j++) interval_tree_insert(nodes + j, &root); for (j = 0; j < NODES; j++) interval_tree_remove(nodes + j, &root); } time2 = get_cycles(); time = time2 - time1; time = div_u64(time, PERF_LOOPS); printk(" -> %llu cycles\n", (unsigned long long)time); printk(KERN_ALERT "interval tree search"); for (j = 0; j < NODES; j++) interval_tree_insert(nodes + j, &root); time1 = get_cycles(); results = 0; for (i = 0; i < SEARCH_LOOPS; i++) for (j = 0; j < SEARCHES; j++) results += search(queries[j], &root); time2 = get_cycles(); time = time2 - time1; time = div_u64(time, SEARCH_LOOPS); results = div_u64(results, SEARCH_LOOPS); printk(" -> %llu cycles (%lu results)\n", (unsigned long long)time, results); return -EAGAIN; /* Fail will directly unload the module */ } static void interval_tree_test_exit(void) { printk(KERN_ALERT "test exit\n"); } module_init(interval_tree_test_init) module_exit(interval_tree_test_exit) MODULE_LICENSE("GPL"); MODULE_AUTHOR("Michel Lespinasse"); MODULE_DESCRIPTION("Interval Tree test"); t/log/net/dccp/minisocks.c'>
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authorIago Abal <mail@iagoabal.eu>2017-01-11 14:00:21 +0100
committerVinod Koul <vinod.koul@intel.com>2017-01-25 15:35:11 +0530
commit91539eb1fda2d530d3b268eef542c5414e54bf1a (patch)
tree960f5ca6342ad20837aff18aad6e8ecd7da32fd6 /net/dccp/minisocks.c
parent6610d0edf6dc7ee97e46ab3a538a565c79d26199 (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 'net/dccp/minisocks.c')