Commit 8c516543 authored Apr 10, 2019 by Scott Wood Committed by Christoph Hellwig Apr 11, 2019

dma-debug: only skip one stackframe entry



With skip set to 1, I get a traceback like this:

[  106.867637] DMA-API: Mapped at:
[  106.870784]  afu_dma_map_region+0x2cd/0x4f0 [dfl_afu]
[  106.875839]  afu_ioctl+0x258/0x380 [dfl_afu]
[  106.880108]  do_vfs_ioctl+0xa9/0x720
[  106.883688]  ksys_ioctl+0x60/0x90
[  106.887007]  __x64_sys_ioctl+0x16/0x20

With the previous value of 2, afu_dma_map_region was being omitted.  I
suspect that the code paths have simply changed since the value of 2 was
chosen a decade ago, but it's also possible that it varies based on which
mapping function was used, compiler inlining choices, etc.  In any case,
it's best to err on the side of skipping less.

Signed-off-by: Scott Wood <swood@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

parent 2a29e9f6

kernel/dma/debug.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -706,7 +706,7 @@ static struct dma_debug_entry *dma_entry_alloc(void)
		#ifdef CONFIG_STACKTRACE
		entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
		entry->stacktrace.entries = entry->st_entries;
		entry->stacktrace.skip = 2;
		entry->stacktrace.skip = 1;
		save_stack_trace(&entry->stacktrace);
		#endif

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