scs: Report SCS usage in bytes rather than number of entries

PATCH In review Will Deacon 2 participants 3 messages Jun 3, 2020 – Jun 4, 2020

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Will Deacon

author

2020-06-03 15:12 UTC #0 lore raw

PATCH 1/1 scs: Report SCS usage in bytes rather than number of entries

Fix the SCS debug usage check so that we report the number of bytes usedm, rather than the number of entries.

Fixes 5bbaf9d1fcb9 ("scs: Add support for stack usage debugging")

Reported-by Sami Tolvanen <[email protected]>

Signed-off-by Will Deacon <[email protected]>

---
 kernel/scs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

kernel/scs.c +1 -1

index 222a7a9ad543..5d4d9bbdec36 100644
@@ -74,7 +74,7 @@ static void scs_check_usage(struct task_struct *tsk)
 	for (p = task_scs(tsk); p < __scs_magic(tsk); ++p) {
 		if (!READ_ONCE_NOCHECK(*p))
 			break;
-		used++;
+		used += sizeof(*p);
 	}
 
 	while (used > curr) {

Signature · 1 line

2.27.0.rc2.251.g90737beb825-goog

Kees Cook

Reviewed-by on v1 1/1

2020-06-03 17:06 UTC #1 lore raw

Quoted 2 lines · Will Deacon

Fix the SCS debug usage check so that we report the number of bytes usedm, rather than the number of entries.

typo: used

Quoted 4 lines

Fixes 5bbaf9d1fcb9 ("scs: Add support for stack usage debugging")
Reported-by Sami Tolvanen <[email protected]>
Signed-off-by Will Deacon <[email protected]>

Reviewed-by Kees Cook <[email protected]>

Signature · 1 line

Kees Cook

Will Deacon

author

2020-06-04 15:15 UTC #2 lore raw

Quoted 4 lines · Kees Cook

Quoted 2 lines · Will Deacon
Fix the SCS debug usage check so that we report the number of bytes usedm, rather than the number of entries.

Quoted 8 lines

typo: used
Quoted 4 lines
Fixes 5bbaf9d1fcb9 ("scs: Add support for stack usage debugging")
Reported-by Sami Tolvanen <[email protected]>
Signed-off-by Will Deacon <[email protected]>
Reviewed-by Kees Cook <[email protected]>

Cheers, Kees!

Will