From: Yonting Lin <linyongting@gmail.com>
To: richard@nod.at, anton.ivanov@cambridgegreys.com,
tiwei.btw@antgroup.com, linux-um@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, linyongting@gmail.com
Subject: [PATCH] um: Fix tgkill compile error on old host OSes
Date: Tue, 27 May 2025 23:12:22 +0800 [thread overview]
Message-ID: <20250527151222.40371-1-linyongting@gmail.com> (raw)
From: Yongting Lin <linyongting@gmail.com>
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>
---
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 a05a6ecee756..6de145f8fe3d 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);
--
2.20.1
reply other threads:[~2025-05-27 15:16 UTC|newest]
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