6.6-stable review patch. If anyone has any objections, please let me know.
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From: Linus Torvalds torvalds@linux-foundation.org
[ Upstream commit a48f822908982353c3256e35a089e9e7d0d61580 ]
Apparently as of version 2.42, glibc headers define AT_RENAME_NOREPLACE and some of the other flags for renameat2() and friends in <stdio.h>.
Which would all be fine, except for inexplicable reasons glibc decided to define them _differently_ from the kernel definitions, which then makes some of our sample code that includes both kernel headers and user space headers unhappy, because the compiler will (correctly) complain about redefining things.
Now, mixing kernel headers and user space headers is always a somewhat iffy proposition due to namespacing issues, but it's kind of inevitable in our sample and selftest code. And this is just glibc being stupid.
Those defines come from the kernel, glibc is exposing the kernel interfaces, and glibc shouldn't make up some random new expressions for these values.
It's not like glibc headers changed the actual result values, but they arbitrarily just decided to use a different expression to describe those values. The kernel just does
#define AT_RENAME_NOREPLACE 0x0001
while glibc does
# define RENAME_NOREPLACE (1 << 0) # define AT_RENAME_NOREPLACE RENAME_NOREPLACE
instead. Same value in the end, but very different macro definition.
For absolutely no reason.
This has since been fixed in the glibc development tree, so eventually we'll end up with the canonical expressions and no clashes. But in the meantime the broken headers are in the glibc-2.42 release and have made it out into distributions.
Do a minimal work-around to make the samples build cleanly by just undefining the affected macros in between the user space header include and the kernel header includes.
Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- samples/vfs/test-statx.c | 6 ++++++ samples/watch_queue/watch_test.c | 6 ++++++ 2 files changed, 12 insertions(+)
diff --git a/samples/vfs/test-statx.c b/samples/vfs/test-statx.c index 49c7a46cee073..424a6fa15723c 100644 --- a/samples/vfs/test-statx.c +++ b/samples/vfs/test-statx.c @@ -19,6 +19,12 @@ #include <time.h> #include <sys/syscall.h> #include <sys/types.h> + +// Work around glibc header silliness +#undef AT_RENAME_NOREPLACE +#undef AT_RENAME_EXCHANGE +#undef AT_RENAME_WHITEOUT + #include <linux/stat.h> #include <linux/fcntl.h> #define statx foo diff --git a/samples/watch_queue/watch_test.c b/samples/watch_queue/watch_test.c index 8c6cb57d5cfc5..24cf7d7a19725 100644 --- a/samples/watch_queue/watch_test.c +++ b/samples/watch_queue/watch_test.c @@ -16,6 +16,12 @@ #include <errno.h> #include <sys/ioctl.h> #include <limits.h> + +// Work around glibc header silliness +#undef AT_RENAME_NOREPLACE +#undef AT_RENAME_EXCHANGE +#undef AT_RENAME_WHITEOUT + #include <linux/watch_queue.h> #include <linux/unistd.h> #include <linux/keyctl.h>