From ba86bf8bfc1add5f515db8cf1d6042bb9396a299 Mon Sep 17 00:00:00 2001 From: Chris Wilson Date: Tue, 20 Oct 2009 16:29:16 +0000 Subject: [PATCH] drm/i915: Avoid potential sleep whilst holding spinlock Miles Lane reported the following error: 2 locks held by cat/4179: #0: (&p->lock){+.+.+.}, at: [] seq_read+0x25/0x315 #1: (&dev_priv->mm.active_list_lock){+.+...}, at: [] i915_batchbuffer_info+0x2b/0x124 Pid: 4179, comm: cat Not tainted 2.6.32-rc5-git1 #2 Call Trace: [] ? __debug_show_held_locks+0x1e/0x20 [] __might_sleep+0xf0/0xf7 [] kmap+0x17/0x58 [] i915_batchbuffer_info+0xad/0x124 [] seq_read+0x160/0x315 [] ? rw_verify_area+0x98/0xbb [] ? seq_read+0x0/0x315 [] vfs_read+0x75/0xa9 [] sys_read+0x3b/0x5d [] sysenter_do_call+0x12/0x36 The fix is relatively simple, use the atomic variants of kmap() that avoid the potential sleep. Signed-off-by: Chris Wilson Cc: Miles Lane Signed-off-by: Eric Anholt --- drivers/gpu/drm/i915/i915_debugfs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index f8ce9a3a420d..26bf0552b3cb 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -267,10 +267,10 @@ static void i915_dump_pages(struct seq_file *m, struct page **pages, int page_co uint32_t *mem; for (page = 0; page < page_count; page++) { - mem = kmap(pages[page]); + mem = kmap_atomic(pages[page], KM_USER0); for (i = 0; i < PAGE_SIZE; i += 4) seq_printf(m, "%08x : %08x\n", i, mem[i / 4]); - kunmap(pages[page]); + kunmap_atomic(pages[page], KM_USER0); } } -- 2.20.1