#include #include "notifier-error-inject.h" static int debugfs_errno_set(void *data, u64 val) { *(int *)data = clamp_t(int, val, -MAX_ERRNO, 0); return 0; } static int debugfs_errno_get(void *data, u64 *val) { *val = *(int *)data; return 0; } DEFINE_SIMPLE_ATTRIBUTE(fops_errno, debugfs_errno_get, debugfs_errno_set, "%lld\n"); static struct dentry *debugfs_create_errno(const char *name, umode_t mode, struct dentry *parent, int *value) { return debugfs_create_file(name, mode, parent, value, &fops_errno); } static int notifier_err_inject_callback(struct notifier_block *nb, unsigned long val, void *p) { int err = 0; struct notifier_err_inject *err_inject = container_of(nb, struct notifier_err_inject, nb); struct notifier_err_inject_action *action; for (action = err_inject->actions; action->name; action++) { if (action->val == val) { err = action->error; break; } } if (err) pr_info("Injecting error (%d) to %s\n", err, action->name); return notifier_from_errno(err); } struct dentry *notifier_err_inject_dir; EXPORT_SYMBOL_GPL(notifier_err_inject_dir); struct dentry *notifier_err_inject_init(const char *name, struct dentry *parent, struct notifier_err_inject *err_inject, int priority) { struct notifier_err_inject_action *action; umode_t mode = S_IFREG | S_IRUSR | S_IWUSR; struct dentry *dir; struct dentry *actions_dir; err_inject->nb.notifier_call = notifier_err_inject_callback; err_inject->nb.priority = priority; dir = debugfs_create_dir(name, parent); if (!dir) return ERR_PTR(-ENOMEM); actions_dir = debugfs_create_dir("actions", dir); if (!actions_dir) goto fail; for (action = err_inject->actions; action->name; action++) { struct dentry *action_dir; action_dir = debugfs_create_dir(action->name, actions_dir); if (!action_dir) goto fail; /* * Create debugfs r/w file containing action->error. If * notifier call chain is called with action->val, it will * fail with the error code */ if (!debugfs_create_errno("error", mode, action_dir, &action->error)) goto fail; } return dir; fail: debugfs_remove_recursive(dir); return ERR_PTR(-ENOMEM); } EXPORT_SYMBOL_GPL(notifier_err_inject_init); static int __init err_inject_init(void) { notifier_err_inject_dir = debugfs_create_dir("notifier-error-inject", NULL); if (!notifier_err_inject_dir) return -ENOMEM; return 0; } static void __exit err_inject_exit(void) { debugfs_remove_recursive(notifier_err_inject_dir); } module_init(err_inject_init); module_exit(err_inject_exit); MODULE_DESCRIPTION("Notifier error injection module"); MODULE_LICENSE("GPL"); MODULE_AUTHOR("Akinobu Mita "); gi/linux/net-next.git/commit/include?id=91539eb1fda2d530d3b268eef542c5414e54bf1a'>include/soc/fsl
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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 /include/soc/fsl
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 'include/soc/fsl')