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authorDavid Howells <dhowells@redhat.com>2023-06-15 12:32:02 +0100
committerJakub Kicinski <kuba@kernel.org>2023-06-17 00:08:27 -0700
commit9f8d0dc0ec4a4b5b78c0be83238c4511ff5f1ae0 (patch)
tree18016d5e845ae50ddd9200f97793cee5b30faf2b /net
parent5a6f6873606e03a0a95afe40ba5e84bb6e28a26f (diff)
kcm: Fix unnecessary psock unreservation.
kcm_write_msgs() calls unreserve_psock() to release its hold on the underlying TCP socket if it has run out of things to transmit, but if we have nothing in the write queue on entry (e.g. because someone did a zero-length sendmsg), we don't actually go into the transmission loop and as a consequence don't call reserve_psock(). Fix this by skipping the call to unreserve_psock() if we didn't reserve a psock. Fixes: c31a25e1db48 ("kcm: Send multiple frags in one sendmsg()") Reported-by: syzbot+dd1339599f1840e4cc65@syzkaller.appspotmail.com Link: https://lore.kernel.org/r/000000000000a61ffe05fe0c3d08@google.com/ Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: syzbot+dd1339599f1840e4cc65@syzkaller.appspotmail.com cc: Tom Herbert <tom@herbertland.com> cc: Tom Herbert <tom@quantonium.net> cc: Jens Axboe <axboe@kernel.dk> cc: Matthew Wilcox <willy@infradead.org> Link: https://lore.kernel.org/r/20787.1686828722@warthog.procyon.org.uk Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/kcm/kcmsock.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index d75d775e9462..d0537c1c8cd7 100644
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -661,6 +661,7 @@ retry:
kcm_abort_tx_psock(psock, ret ? -ret : EPIPE,
true);
unreserve_psock(kcm);
+ psock = NULL;
txm->started_tx = false;
kcm_report_tx_retry(kcm);
@@ -696,7 +697,8 @@ out:
if (!head) {
/* Done with all queued messages. */
WARN_ON(!skb_queue_empty(&sk->sk_write_queue));
- unreserve_psock(kcm);
+ if (psock)
+ unreserve_psock(kcm);
}
/* Check if write space is available */