We need to protect not only the list, but the individual map_obj's. Otherwise, we might be building the scatter-gather list while the map_obj is being destroyed.
I observed race conditions which caused kernel panics while running stress tests. This patch fixes those. Signed-off-by: Felipe Contreras <[email protected]> --- drivers/staging/tidspbridge/rmgr/proc.c | 15 +++++++++++---- 1 files changed, 11 insertions(+), 4 deletions(-) diff --git a/drivers/staging/tidspbridge/rmgr/proc.c b/drivers/staging/tidspbridge/rmgr/proc.c index 77ab5f5..ea2d105 100644 --- a/drivers/staging/tidspbridge/rmgr/proc.c +++ b/drivers/staging/tidspbridge/rmgr/proc.c @@ -203,6 +203,7 @@ static int match_containing_map_obj(struct dmm_map_object *map_obj, mpu_addr + size <= map_obj_end; } +/* must be called while holding dmm_map semaphore */ static struct dmm_map_object *find_containing_mapping( struct process_context *pr_ctxt, u32 mpu_addr, u32 size) @@ -211,7 +212,6 @@ static struct dmm_map_object *find_containing_mapping( pr_debug("%s: looking for mpu_addr 0x%x size 0x%x\n", __func__, mpu_addr, size); - down(&pr_ctxt->dmm_map_sema); list_for_each_entry(map_obj, &pr_ctxt->dmm_map_list, link) { pr_debug("%s: candidate: mpu_addr 0x%x virt 0x%x size 0x%x\n", __func__, @@ -228,7 +228,6 @@ static struct dmm_map_object *find_containing_mapping( map_obj = NULL; out: - up(&pr_ctxt->dmm_map_sema); return map_obj; } @@ -781,12 +780,14 @@ int proc_begin_dma(void *hprocessor, void *pmpu_addr, u32 ul_size, (u32)pmpu_addr, ul_size, dir); + down(&pr_ctxt->dmm_map_sema); + /* find requested memory are in cached mapping information */ map_obj = find_containing_mapping(pr_ctxt, (u32) pmpu_addr, ul_size); if (!map_obj) { pr_err("%s: find_containing_mapping failed\n", __func__); status = -EFAULT; - goto err_out; + goto no_map; } if (memory_give_ownership(map_obj, (u32) pmpu_addr, ul_size, dir)) { @@ -795,6 +796,8 @@ int proc_begin_dma(void *hprocessor, void *pmpu_addr, u32 ul_size, status = -EFAULT; } +no_map: + up(&pr_ctxt->dmm_map_sema); err_out: return status; @@ -819,12 +822,14 @@ int proc_end_dma(void *hprocessor, void *pmpu_addr, u32 ul_size, (u32)pmpu_addr, ul_size, dir); + down(&pr_ctxt->dmm_map_sema); + /* find requested memory are in cached mapping information */ map_obj = find_containing_mapping(pr_ctxt, (u32) pmpu_addr, ul_size); if (!map_obj) { pr_err("%s: find_containing_mapping failed\n", __func__); status = -EFAULT; - goto err_out; + goto no_map; } if (memory_regain_ownership(map_obj, (u32) pmpu_addr, ul_size, dir)) { @@ -834,6 +839,8 @@ int proc_end_dma(void *hprocessor, void *pmpu_addr, u32 ul_size, goto err_out; } +no_map: + up(&pr_ctxt->dmm_map_sema); err_out: return status; } -- 1.7.3.3 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
