This is a note to let you know that I've just added the patch titled
libbpf: Fix faccessat() usage on Android
to the 6.6-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:
libbpf-fix-faccessat-usage-on-android.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f28a5e181eff29bb700039a3e5b5ff198ab38970
Author: Andrii Nakryiko <andrii@xxxxxxxxxx>
Date: Fri Jan 26 14:09:44 2024 -0800
libbpf: Fix faccessat() usage on Android
[ Upstream commit ad57654053805bf9a62602aaec74cc78edb6f235 ]
Android implementation of libc errors out with -EINVAL in faccessat() if
passed AT_EACCESS ([0]), this leads to ridiculous issue with libbpf
refusing to load /sys/kernel/btf/vmlinux on Androids ([1]). Fix by
detecting Android and redefining AT_EACCESS to 0, it's equivalent on
Android.
[0] https://android.googlesource.com/platform/bionic/+/refs/heads/android13-release/libc/bionic/faccessat.cpp#50
[1] https://github.com/libbpf/libbpf-bootstrap/issues/250#issuecomment-1911324250
Fixes: 6a4ab8869d0b ("libbpf: Fix the case of running as non-root with capabilities")
Signed-off-by: Andrii Nakryiko <andrii@xxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Link: https://lore.kernel.org/bpf/20240126220944.2497665-1-andrii@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h
index f0f08635adb0d..57dec645d6878 100644
--- a/tools/lib/bpf/libbpf_internal.h
+++ b/tools/lib/bpf/libbpf_internal.h
@@ -18,6 +18,20 @@
#include <libelf.h>
#include "relo_core.h"
+/* Android's libc doesn't support AT_EACCESS in faccessat() implementation
+ * ([0]), and just returns -EINVAL even if file exists and is accessible.
+ * See [1] for issues caused by this.
+ *
+ * So just redefine it to 0 on Android.
+ *
+ * [0] https://android.googlesource.com/platform/bionic/+/refs/heads/android13-release/libc/bionic/faccessat.cpp#50
+ * [1] https://github.com/libbpf/libbpf-bootstrap/issues/250#issuecomment-1911324250
+ */
+#ifdef __ANDROID__
+#undef AT_EACCESS
+#define AT_EACCESS 0
+#endif
+
/* make sure libbpf doesn't use kernel-only integer typedefs */
#pragma GCC poison u8 u16 u32 u64 s8 s16 s32 s64
