From: David Howells <dhowells@redhat.com>
To: netdev@vger.kernel.org
Cc: Marc Dionne <marc.dionne@auristor.com>,
linux-afs@lists.infradead.org, dhowells@redhat.com,
linux-afs@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH net 2/6] rxrpc: Fix listen() setting the bar too high for the prealloc rings
Date: Fri, 20 May 2022 17:33:55 +0100 [thread overview]
Message-ID: <165306443567.34086.5831728738832363232.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <165306442115.34086.1818959430525328753.stgit@warthog.procyon.org.uk>
AF_RXRPC's listen() handler lets you set the backlog up to 32 (if you bump
up the sysctl), but whilst the preallocation circular buffers have 32 slots
in them, one of them has to be a dead slot because we're using CIRC_CNT().
This means that listen(rxrpc_sock, 32) will cause an oops when the socket
is closed because rxrpc_service_prealloc_one() allocated one too many calls
and rxrpc_discard_prealloc() won't then be able to get rid of them because
it'll think the ring is empty. rxrpc_release_calls_on_socket() then tries
to abort them, but oopses because call->peer isn't yet set.
Fix this by setting the maximum backlog to RXRPC_BACKLOG_MAX - 1 to match
the ring capacity.
BUG: kernel NULL pointer dereference, address: 0000000000000086
...
RIP: 0010:rxrpc_send_abort_packet+0x73/0x240 [rxrpc]
Call Trace:
<TASK>
? __wake_up_common_lock+0x7a/0x90
? rxrpc_notify_socket+0x8e/0x140 [rxrpc]
? rxrpc_abort_call+0x4c/0x60 [rxrpc]
rxrpc_release_calls_on_socket+0x107/0x1a0 [rxrpc]
rxrpc_release+0xc9/0x1c0 [rxrpc]
__sock_release+0x37/0xa0
sock_close+0x11/0x20
__fput+0x89/0x240
task_work_run+0x59/0x90
do_exit+0x319/0xaa0
Fixes: 00e907127e6f ("rxrpc: Preallocate peers, conns and calls for incoming service requests")
Reported-by: Marc Dionne <marc.dionne@auristor.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: linux-afs@lists.infradead.org
Link: https://lists.infradead.org/pipermail/linux-afs/2022-March/005079.html
---
net/rxrpc/sysctl.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/net/rxrpc/sysctl.c b/net/rxrpc/sysctl.c
index 540351d6a5f4..555e0910786b 100644
--- a/net/rxrpc/sysctl.c
+++ b/net/rxrpc/sysctl.c
@@ -12,7 +12,7 @@
static struct ctl_table_header *rxrpc_sysctl_reg_table;
static const unsigned int four = 4;
-static const unsigned int thirtytwo = 32;
+static const unsigned int max_backlog = RXRPC_BACKLOG_MAX - 1;
static const unsigned int n_65535 = 65535;
static const unsigned int n_max_acks = RXRPC_RXTX_BUFF_SIZE - 1;
static const unsigned long one_jiffy = 1;
@@ -89,7 +89,7 @@ static struct ctl_table rxrpc_sysctl_table[] = {
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra1 = (void *)&four,
- .extra2 = (void *)&thirtytwo,
+ .extra2 = (void *)&max_backlog,
},
{
.procname = "rx_window_size",
next prev parent reply other threads:[~2022-05-20 16:34 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-20 16:33 [PATCH net 0/6] rxrpc: Leak fixes David Howells
2022-05-20 16:33 ` [PATCH net 1/6] rxrpc: Enable IPv6 checksums on transport socket David Howells
2022-05-21 1:15 ` Jakub Kicinski
2022-05-21 7:27 ` David Howells
2022-05-20 16:33 ` David Howells [this message]
2022-05-20 16:34 ` [PATCH net 3/6] rxrpc: Don't try to resend the request if we're receiving the reply David Howells
2022-05-20 16:34 ` [PATCH net 4/6] rxrpc: Fix overlapping ACK accounting David Howells
2022-05-20 16:34 ` [PATCH net 5/6] rxrpc: Don't let ack.previousPacket regress David Howells
2022-05-20 16:34 ` [PATCH net 6/6] rxrpc: Fix decision on when to generate an IDLE ACK David Howells
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