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authorDavid Howells <dhowells@redhat.com>2017-08-18 00:19:42 +0100
committerDavid S. Miller <davem@davemloft.net>2017-08-18 16:23:23 -0700
commit9a19bad70cf16b0cdf3576efda7deb490e7aa529 (patch)
treea8d36862dae81b010cd8bc41c9cf996d66829124 /net/rxrpc
parentb024d949a3c24255a7ef1a470420eb478949aa4c (diff)
downloadlinux-rt-9a19bad70cf16b0cdf3576efda7deb490e7aa529.tar.gz
rxrpc: Fix oops when discarding a preallocated service call
rxrpc_service_prealloc_one() doesn't set the socket pointer on any new call it preallocates, but does add it to the rxrpc net namespace call list. This, however, causes rxrpc_put_call() to oops when the call is discarded when the socket is closed. rxrpc_put_call() needs the socket to be able to reach the namespace so that it can use a lock held therein. Fix this by setting a call's socket pointer immediately before discarding it. This can be triggered by unloading the kafs module, resulting in an oops like the following: BUG: unable to handle kernel NULL pointer dereference at 0000000000000030 IP: rxrpc_put_call+0x1e2/0x32d PGD 0 P4D 0 Oops: 0000 [#1] SMP Modules linked in: kafs(E-) CPU: 3 PID: 3037 Comm: rmmod Tainted: G E 4.12.0-fscache+ #213 Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014 task: ffff8803fc92e2c0 task.stack: ffff8803fef74000 RIP: 0010:rxrpc_put_call+0x1e2/0x32d RSP: 0018:ffff8803fef77e08 EFLAGS: 00010282 RAX: 0000000000000000 RBX: ffff8803fab99ac0 RCX: 000000000000000f RDX: ffffffff81c50a40 RSI: 000000000000000c RDI: ffff8803fc92ea88 RBP: ffff8803fef77e30 R08: ffff8803fc87b941 R09: ffffffff82946d20 R10: ffff8803fef77d10 R11: 00000000000076fc R12: 0000000000000005 R13: ffff8803fab99c20 R14: 0000000000000001 R15: ffffffff816c6aee FS: 00007f915a059700(0000) GS:ffff88041fb80000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000030 CR3: 00000003fef39000 CR4: 00000000001406e0 Call Trace: rxrpc_discard_prealloc+0x325/0x341 rxrpc_listen+0xf9/0x146 kernel_listen+0xb/0xd afs_close_socket+0x3e/0x173 [kafs] afs_exit+0x1f/0x57 [kafs] SyS_delete_module+0x10f/0x19a do_syscall_64+0x8a/0x149 entry_SYSCALL64_slow_path+0x25/0x25 Fixes: 2baec2c3f854 ("rxrpc: Support network namespacing") Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/rxrpc')
-rw-r--r--net/rxrpc/call_accept.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/net/rxrpc/call_accept.c b/net/rxrpc/call_accept.c
index dd30d74824b0..ec3383f97d4c 100644
--- a/net/rxrpc/call_accept.c
+++ b/net/rxrpc/call_accept.c
@@ -223,6 +223,7 @@ void rxrpc_discard_prealloc(struct rxrpc_sock *rx)
tail = b->call_backlog_tail;
while (CIRC_CNT(head, tail, size) > 0) {
struct rxrpc_call *call = b->call_backlog[tail];
+ call->socket = rx;
if (rx->discard_new_call) {
_debug("discard %lx", call->user_call_ID);
rx->discard_new_call(call, call->user_call_ID);