6.15-stable review patch. If anyone has any objections, please let me know.
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From: Yongting Lin linyongting@gmail.com
[ Upstream commit fd054188999ff19746cc09f4e0f196a113964db9 ]
tgkill is a quite old syscall since kernel 2.5.75, but unfortunately glibc doesn't support it before 2.30. Thus some systems fail to compile the latest UserMode Linux.
Here is the compile error I encountered when I tried to compile UML in my system shipped with glibc-2.28.
CALL scripts/checksyscalls.sh CC arch/um/os-Linux/sigio.o In file included from arch/um/os-Linux/sigio.c:17: arch/um/os-Linux/sigio.c: In function ‘write_sigio_thread’: arch/um/os-Linux/sigio.c:49:19: error: implicit declaration of function ‘tgkill’; did you mean ‘kill’? [-Werror=implicit-function-declaration] CATCH_EINTR(r = tgkill(pid, pid, SIGIO)); ^~~~~~ ./arch/um/include/shared/os.h:21:48: note: in definition of macro ‘CATCH_EINTR’ #define CATCH_EINTR(expr) while ((errno = 0, ((expr) < 0)) && (errno == EINTR)) ^~~~ cc1: some warnings being treated as errors
Fix it by Replacing glibc call with raw syscall.
Fixes: 33c9da5dfb18 ("um: Rewrite the sigio workaround based on epoll and tgkill") Signed-off-by: Yongting Lin linyongting@gmail.com Link: https://patch.msgid.link/20250527151222.40371-1-linyongting@gmail.com Signed-off-by: Johannes Berg johannes.berg@intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/um/os-Linux/sigio.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/um/os-Linux/sigio.c b/arch/um/os-Linux/sigio.c index a05a6ecee7561..6de145f8fe3d9 100644 --- a/arch/um/os-Linux/sigio.c +++ b/arch/um/os-Linux/sigio.c @@ -12,6 +12,7 @@ #include <signal.h> #include <string.h> #include <sys/epoll.h> +#include <asm/unistd.h> #include <kern_util.h> #include <init.h> #include <os.h> @@ -46,7 +47,7 @@ static void *write_sigio_thread(void *unused) __func__, errno); }
- CATCH_EINTR(r = tgkill(pid, pid, SIGIO)); + CATCH_EINTR(r = syscall(__NR_tgkill, pid, pid, SIGIO)); if (r < 0) printk(UM_KERN_ERR "%s: tgkill failed, errno = %d\n", __func__, errno);