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authorJohannes Berg <johannes.berg@intel.com>2022-05-20 20:45:36 +0300
committerRichard Weinberger <richard@nod.at>2022-05-27 10:03:41 +0300
commit57ae0b67b747031bc41fb44643aa5344ab58607e (patch)
tree1e9d908c43466f475d90e4e0cc01249e8b11afcb /arch/um/drivers
parentaf9fb41ed315ce95f659f0b10b4d59a71975381d (diff)
downloadlinux-57ae0b67b747031bc41fb44643aa5344ab58607e.tar.xz
um: chan_user: Fix winch_tramp() return value
The previous fix here was only partially correct, it did result in returning a proper error value in case of error, but it also clobbered the pid that we need to return from this function (not just zero for success). As a result, it returned 0 here, but later this is treated as a pid and used to kill the process, but since it's now 0 we kill(0, SIGKILL), which makes UML kill itself rather than just the helper thread. Fix that and make it more obvious by using a separate variable for the pid. Fixes: ccf1236ecac4 ("um: fix error return code in winch_tramp()") Reported-and-tested-by: Nathan Chancellor <nathan@kernel.org> Signed-off-by: Johannes Berg <johannes.berg@intel.com> Cc: stable@vger.kernel.org Signed-off-by: Richard Weinberger <richard@nod.at>
Diffstat (limited to 'arch/um/drivers')
-rw-r--r--arch/um/drivers/chan_user.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/arch/um/drivers/chan_user.c b/arch/um/drivers/chan_user.c
index 6040817c036f..25727ed648b7 100644
--- a/arch/um/drivers/chan_user.c
+++ b/arch/um/drivers/chan_user.c
@@ -220,7 +220,7 @@ static int winch_tramp(int fd, struct tty_port *port, int *fd_out,
unsigned long *stack_out)
{
struct winch_data data;
- int fds[2], n, err;
+ int fds[2], n, err, pid;
char c;
err = os_pipe(fds, 1, 1);
@@ -238,8 +238,9 @@ static int winch_tramp(int fd, struct tty_port *port, int *fd_out,
* problem with /dev/net/tun, which if held open by this
* thread, prevents the TUN/TAP device from being reused.
*/
- err = run_helper_thread(winch_thread, &data, CLONE_FILES, stack_out);
- if (err < 0) {
+ pid = run_helper_thread(winch_thread, &data, CLONE_FILES, stack_out);
+ if (pid < 0) {
+ err = pid;
printk(UM_KERN_ERR "fork of winch_thread failed - errno = %d\n",
-err);
goto out_close;
@@ -263,7 +264,7 @@ static int winch_tramp(int fd, struct tty_port *port, int *fd_out,
goto out_close;
}
- return err;
+ return pid;
out_close:
close(fds[1]);