[PATCH] sched_getattr.2: update to include changed size semantics
From: Aleksa Sarai <hidden>
Date: 2019-11-28 12:09:32
Subsystem:
the rest · Maintainer:
Linus Torvalds
From: Aleksa Sarai <hidden>
Date: 2019-11-28 12:09:32
Subsystem:
the rest · Maintainer:
Linus Torvalds
Due to a userspace breakage, commit 1251201c0d34 ("sched/core: Fix
uclamp ABI bug, clean up and robustify sched_read_attr() ABI logic and
code") changed the semantics of sched_getattr(2) when the userspace
struct is smaller than the kernel struct. Now, any trailing non-zero
data in the kernel structure is ignored when copying to userspace.
Ref: 1251201c0d34 ("sched/core: Fix uclamp ABI bug, clean up and
robustify sched_read_attr() ABI logic and code")
Signed-off-by: Aleksa Sarai <redacted>
---
man2/sched_setattr.2 | 6 ++----
1 file changed, 2 insertions(+), 4 deletions(-)
diff --git a/man2/sched_setattr.2 b/man2/sched_setattr.2
index 76ffa14eba85..fbb67b8eb98b 100644
--- a/man2/sched_setattr.2
+++ b/man2/sched_setattr.2@@ -284,10 +284,8 @@ structure, the additional bytes in the user-space structure are not touched. If the caller-provided structure is smaller than the kernel .I sched_attr -structure and the kernel needs to return values outside the provided space, -.BR sched_getattr () -fails with the error -.BR E2BIG . +structure, the kernel will silently not return any values which would be stored +outside the provided space. As with .BR sched_setattr (), these semantics allow for future extensibility of the interface.
--
2.24.0