[PATCH 5.17 0742/1126] dma-debug: fix return value of __setup handlers

From: Greg Kroah-Hartman
Date: Tue Apr 05 2022 - 05:51:00 EST

From: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>

[ Upstream commit 80e4390981618e290616dbd06ea190d4576f219d ]

When valid kernel command line parameters
dma_debug=off dma_debug_entries=100
are used, they are reported as Unknown parameters and added to init's
environment strings, polluting it.

Unknown kernel command line parameters "BOOT_IMAGE=/boot/bzImage-517rc5
dma_debug=off dma_debug_entries=100", will be passed to user space.


Run /sbin/init as init process
with arguments:
with environment:

Return 1 from these __setup handlers to indicate that the command line
option has been handled.

Fixes: 59d3daafa1726 ("dma-debug: add kernel command line parameters")
Signed-off-by: Randy Dunlap <rdunlap@xxxxxxxxxxxxx>
Reported-by: Igor Zhbanov <i.zhbanov@xxxxxxxxxxxx>
Link: lore.kernel.org/r/64644a2f-4a20-bab3-1e15-3b2cdd0defe3@xxxxxxxxxxxx
Cc: Joerg Roedel <joro@xxxxxxxxxx>
Cc: Christoph Hellwig <hch@xxxxxx>
Cc: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
Cc: iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx
Cc: Robin Murphy <robin.murphy@xxxxxxx>
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
kernel/dma/debug.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
index 7a14ca29c377..f8ff598596b8 100644
--- a/kernel/dma/debug.c
+++ b/kernel/dma/debug.c
@@ -927,7 +927,7 @@ static __init int dma_debug_cmdline(char *str)
global_disable = true;

- return 0;
+ return 1;

static __init int dma_debug_entries_cmdline(char *str)
@@ -936,7 +936,7 @@ static __init int dma_debug_entries_cmdline(char *str)
return -EINVAL;
if (!get_option(&str, &nr_prealloc_entries))
nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
- return 0;
+ return 1;

__setup("dma_debug=", dma_debug_cmdline);