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| author | Johannes Berg <johannes.berg@intel.com> | 2022-05-20 19:45:36 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-06-14 16:59:29 +0200 |
| commit | f8dddfcdbc46796ef469031ef4182669a6dd3919 (patch) | |
| tree | f3d4e69d5945f45889af7fe5fd2cbc0ec48f91cc /arch/um | |
| parent | d766673961c57c8b2e97c41451306b1bca452135 (diff) | |
| download | linux-stable-f8dddfcdbc46796ef469031ef4182669a6dd3919.tar.gz linux-stable-f8dddfcdbc46796ef469031ef4182669a6dd3919.tar.bz2 linux-stable-f8dddfcdbc46796ef469031ef4182669a6dd3919.zip | |
um: chan_user: Fix winch_tramp() return value
commit 57ae0b67b747031bc41fb44643aa5344ab58607e upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/um')
| -rw-r--r-- | arch/um/drivers/chan_user.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/arch/um/drivers/chan_user.c b/arch/um/drivers/chan_user.c index 669124d5290b..b3f320a129e3 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]); |