# HG changeset patch
# User Sebastian Wiedenroth <sebastian.wiedenroth at skylime.net>
# Date 1437050484 -7200
# Thu Jul 16 14:41:24 2015 +0200
# Node ID 7ef3a533b097e8e6590e754dc56ad308ab29233b
# Parent e3640ccaa76d77a9658126d1f8f306480dad8af7
Fix hang in safe_sendfile on SmartOS
The call to sendfile on SmartOS can fail with EOPNOTSUPP. This is a valid error
code and documented in the man page. This error code needs to be handled or
else dovecot will retry the sendfile call endlessly and hang.
diff -r e3640ccaa76d -r 7ef3a533b097 src/lib/sendfile-util.c
--- a/src/lib/sendfile-util.c Sat Jan 10 04:32:42 2015 +0200
+++ b/src/lib/sendfile-util.c Thu Jul 16 14:41:24 2015 +0200
@@ -116,7 +116,7 @@
if (errno == EINVAL) {
/* most likely trying to read past EOF */
ret = 0;
- } else if (errno == EAFNOSUPPORT) {
+ } else if (errno == EAFNOSUPPORT || errno == EOPNOTSUPP) {
/* not supported, return Linux-like EINVAL so caller
sees only consistent errnos. */
errno = EINVAL;
ping? If more information or a system to test the issue on is required please let me know, I?m sure I can provide those. If this list is not the correct place for patches I?m also happy to learn where else to send it. Thanks. Best regards, Sebastian> Am 16.07.2015 um 17:03 schrieb Sebastian Wiedenroth <sebastian.wiedenroth at skylime.net>: > > # HG changeset patch > # User Sebastian Wiedenroth <sebastian.wiedenroth at skylime.net> > # Date 1437050484 -7200 > # Thu Jul 16 14:41:24 2015 +0200 > # Node ID 7ef3a533b097e8e6590e754dc56ad308ab29233b > # Parent e3640ccaa76d77a9658126d1f8f306480dad8af7 > Fix hang in safe_sendfile on SmartOS > > The call to sendfile on SmartOS can fail with EOPNOTSUPP. This is a valid error > code and documented in the man page. This error code needs to be handled or > else dovecot will retry the sendfile call endlessly and hang. > > diff -r e3640ccaa76d -r 7ef3a533b097 src/lib/sendfile-util.c > --- a/src/lib/sendfile-util.c Sat Jan 10 04:32:42 2015 +0200 > +++ b/src/lib/sendfile-util.c Thu Jul 16 14:41:24 2015 +0200 > @@ -116,7 +116,7 @@ > if (errno == EINVAL) { > /* most likely trying to read past EOF */ > ret = 0; > - } else if (errno == EAFNOSUPPORT) { > + } else if (errno == EAFNOSUPPORT || errno == EOPNOTSUPP) { > /* not supported, return Linux-like EINVAL so caller > sees only consistent errnos. */ > errno = EINVAL; >
On 07/16/2015 06:03 PM, Sebastian Wiedenroth wrote:> Fix hang in safe_sendfile on SmartOS > > The call to sendfile on SmartOS can fail with EOPNOTSUPP. This is a valid error > code and documented in the man page. This error code needs to be handled or > else dovecot will retry the sendfile call endlessly and hang.Committed .. However, I think a more important bug is that it hangs. It's definitely not supposed to hang. Which process was it that was hanging How can I reproduce that? I can only get it to disconnect the IMAP client.
> Am 07.09.2015 um 21:34 schrieb Timo Sirainen <tss at iki.fi>: > > On 07/16/2015 06:03 PM, Sebastian Wiedenroth wrote: >> Fix hang in safe_sendfile on SmartOS >> >> The call to sendfile on SmartOS can fail with EOPNOTSUPP. This is a valid error >> code and documented in the man page. This error code needs to be handled or >> else dovecot will retry the sendfile call endlessly and hang. > > Committed .. However, I think a more important bug is that it hangs. > It's definitely not supposed to hang. Which process was it that was > hanging How can I reproduce that? I can only get it to disconnect the > IMAP client.Thanks! It was the managesieve process that was hanging. To trigger it we used sieve-connect [1] like this: sieve-connect -u demo at example.com mailbox.example.com To find the issue we used a dtrace script [2]. With an unpatched version it would show: CPU ID FUNCTION:NAME 0 4623 safe_sendfile:return 7 4 fffffd7fffdff8b8 154 -> 77 0 4623 safe_sendfile:return 7 4 fffffd7fffdff8b8 9223372036854775807 -> 77 0 4623 safe_sendfile:return 7 4 fffffd7fffdff8b8 9223372036854775807 -> 77 and then just repeat the last line as it retried the call forever. This is where it hangs, spinning on the cpu. After looking at the code I confirmed the issue with a dtrace one-liner that tracks the sendfilev syscall: dtrace -n 'syscall::sendfilev:return {printf("%d %x\n", arg0, errno)}' This showed that the call returned with EOPNOTSUPP (0x7a): 0 6155 sendfilev:return -1 7a The man page lists this as a valid error code and handling it the same way as EAFNOSUPPORT fixed the issue for us. There are a few more error codes in the man page that currently are not handled by dovecot. This might be something to look into in the future. I hope this answer provides the details you?re looking for. Best regards, Sebastian [1] https://github.com/philpennock/sieve-connect [2] https://gist.github.com/wiedi/4b4ebe5f92ac5b54951b