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>

diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index 45d51e8e26f62f27b8b91c3e53ddb2df20fd791b..a218e43cc38258ae6d7bed19f0d6e2ea852e2ac7 100644 (file)
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c
@@ -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