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Subject[PATCH AUTOSEL 6.1 02/18] bpf: Print a warning only if writing to unprivileged_bpf_disabled.
Date
From: Kui-Feng Lee <thinker.li@gmail.com>

[ 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@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yhs@fb.com>
Link: https://lore.kernel.org/bpf/20230502181418.308479-1-kuifeng@meta.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
kernel/bpf/syscall.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
index 6c61dba26f4d9..f04e1f1fc4b6b 100644
--- a/kernel/bpf/syscall.c
+++ b/kernel/bpf/syscall.c
@@ -5284,7 +5284,8 @@ 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;
}
--
2.39.2
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