commit b8ecf4ddd6533437020c4589a6f7bcd9a62307ad
Author: Miroslav Lichvar <mlichvar@redhat.com>
Date:   Tue Sep 13 13:44:10 2022 +0200

    sk: Handle EINTR when waiting for transmit timestamp.
    
    If ptp4l received a signal in poll() waiting for a transmit timestamp,
    multiple (possibly confusing) error messages are logged before exit.
    
    If poll() returns with EINTR, call it once again to get the timestamp
    and avoid logging the errors. Don't call it in a loop to avoid getting
    stuck in case the timestamp is lost and the signal is repeated before
    the poll timeout can be reached.
    
    Signed-off-by: Miroslav Lichvar <mlichvar@redhat.com>

diff --git a/sk.c b/sk.c
index 8be0708..3595649 100644
--- a/sk.c
+++ b/sk.c
@@ -349,6 +349,9 @@ int sk_receive(int fd, void *buf, int buflen,
 	if (flags == MSG_ERRQUEUE) {
 		struct pollfd pfd = { fd, sk_events, 0 };
 		res = poll(&pfd, 1, sk_tx_timeout);
+		/* Retry once on EINTR to avoid logging errors before exit */
+		if (res < 0 && errno == EINTR)
+			res = poll(&pfd, 1, sk_tx_timeout);
 		if (res < 1) {
 			pr_err(res ? "poll for tx timestamp failed: %m" :
 			             "timed out while polling for tx timestamp");