This is a note to let you know that I've just added the patch titled
bpf: Print a warning only if writing to unprivileged_bpf_disabled.
to the 6.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
bpf-print-a-warning-only-if-writing-to-unprivileged_.patch
and it can be found in the queue-6.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 5546963a3ee78475dff4b222fafb27b5ad6d2de2
Author: Kui-Feng Lee <thinker.li@xxxxxxxxx>
Date: Tue May 2 11:14:18 2023 -0700
bpf: Print a warning only if writing to unprivileged_bpf_disabled.
[ Upstream commit fedf99200ab086c42a572fca1d7266b06cdc3e3f ]
Only print the warning message if you are writing to
"/proc/sys/kernel/unprivileged_bpf_disabled".
The kernel may print an annoying warning when you read
"/proc/sys/kernel/unprivileged_bpf_disabled" saying
WARNING: Unprivileged eBPF is enabled with eIBRS on, data leaks possible
via Spectre v2 BHB attacks!
However, this message is only meaningful when the feature is
disabled or enabled.
Signed-off-by: Kui-Feng Lee <kuifeng@xxxxxxxx>
Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Acked-by: Yonghong Song <yhs@xxxxxx>
Link: https://lore.kernel.org/bpf/20230502181418.308479-1-kuifeng@xxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index f1c8733f76b83..5524fcf6fb2a4 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -5394,7 +5394,8 @@ static int bpf_unpriv_handler(struct ctl_table *table, int write,
*(int *)table->data = unpriv_enable;
}
- unpriv_ebpf_notify(unpriv_enable);
+ if (write)
+ unpriv_ebpf_notify(unpriv_enable);
return ret;
}
