[PATCH 6.4 716/800] lib: dhry: fix sleeping allocations inside non-preemptable section

Greg Kroah-Hartman
2023-07-16T20:26:21Z

From: Geert Uytterhoeven <geert+renesas@glider.be>

[ Upstream commit 8ba388c06bc8056935ec1814b2689bfb42f3b89a ]

The Smatch static checker reports the following warnings:

lib/dhry_run.c:38 dhry_benchmark() warn: sleeping in atomic context
lib/dhry_run.c:43 dhry_benchmark() warn: sleeping in atomic context

Indeed, dhry() does sleeping allocations inside the non-preemptable
section delimited by get_cpu()/put_cpu().

Fix this by using atomic allocations instead.
Add error handling, as atomic these allocations may fail.

Link: https://lkml.kernel.org/r/bac6d517818a7cd8efe217c1ad649fffab9cc371.1688568764.git.geert+renesas@glider.be
Fixes: 13684e966d46283e ("lib: dhry: fix unstable smp_processor_id(_) usage")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Closes: https://lore.kernel.org/r/0469eb3a-02eb-4b41-b189-de20b931fa56@moroto.mountain
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
lib/dhry_1.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/lib/dhry_1.c b/lib/dhry_1.c
index 83247106824cc..08edbbb19f573 100644
--- a/lib/dhry_1.c
+++ b/lib/dhry_1.c
@@ -139,8 +139,15 @@ int dhry(int n)

/* Initializations */

- Next_Ptr_Glob = (Rec_Pointer)kzalloc(sizeof(Rec_Type), GFP_KERNEL);
- Ptr_Glob = (Rec_Pointer)kzalloc(sizeof(Rec_Type), GFP_KERNEL);
+ Next_Ptr_Glob = (Rec_Pointer)kzalloc(sizeof(Rec_Type), GFP_ATOMIC);
+ if (!Next_Ptr_Glob)
+ return -ENOMEM;
+
+ Ptr_Glob = (Rec_Pointer)kzalloc(sizeof(Rec_Type), GFP_ATOMIC);
+ if (!Ptr_Glob) {
+ kfree(Next_Ptr_Glob);
+ return -ENOMEM;
+ }

Ptr_Glob->Ptr_Comp = Next_Ptr_Glob;
Ptr_Glob->Discr = Ident_1;
--
2.39.2