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author | David Howells <dhowells@redhat.com> | 2019-04-30 08:34:08 +0100 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-05-08 07:20:44 +0200 |
commit | ccb784fd2248122501c9e19aa5ea2329e987ec7d (patch) | |
tree | 3441c7ed8106a04e18be20ae24dd07fe5e0115cd | |
parent | 882e20df08ccf05fa3e4da759ea6b680e1aef7b6 (diff) | |
download | linux-stable-ccb784fd2248122501c9e19aa5ea2329e987ec7d.tar.gz linux-stable-ccb784fd2248122501c9e19aa5ea2329e987ec7d.tar.bz2 linux-stable-ccb784fd2248122501c9e19aa5ea2329e987ec7d.zip |
rxrpc: Fix net namespace cleanup
[ Upstream commit b13023421b5179413421333f602850914f6a7ad8 ]
In rxrpc_destroy_all_calls(), there are two phases: (1) make sure the
->calls list is empty, emitting error messages if not, and (2) wait for the
RCU cleanup to happen on outstanding calls (ie. ->nr_calls becomes 0).
To avoid taking the call_lock, the function prechecks ->calls and if empty,
it returns to avoid taking the lock - this is wrong, however: it still
needs to go and do the second phase and wait for ->nr_calls to become 0.
Without this, the rxrpc_net struct may get deallocated before we get to the
RCU cleanup for the last calls. This can lead to:
Slab corruption (Not tainted): kmalloc-16k start=ffff88802b178000, len=16384
050: 6b 6b 6b 6b 6b 6b 6b 6b 61 6b 6b 6b 6b 6b 6b 6b kkkkkkkkakkkkkkk
Note the "61" at offset 0x58. This corresponds to the ->nr_calls member of
struct rxrpc_net (which is >9k in size, and thus allocated out of the 16k
slab).
Fix this by flipping the condition on the if-statement, putting the locked
section inside the if-body and dropping the return from there. The
function will then always go on to wait for the RCU cleanup on outstanding
calls.
Fixes: 2baec2c3f854 ("rxrpc: Support network namespacing")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r-- | net/rxrpc/call_object.c | 32 |
1 files changed, 16 insertions, 16 deletions
diff --git a/net/rxrpc/call_object.c b/net/rxrpc/call_object.c index 8a5a42e8ec23..ddaa471a2607 100644 --- a/net/rxrpc/call_object.c +++ b/net/rxrpc/call_object.c @@ -684,27 +684,27 @@ void rxrpc_destroy_all_calls(struct rxrpc_net *rxnet) _enter(""); - if (list_empty(&rxnet->calls)) - return; + if (!list_empty(&rxnet->calls)) { + write_lock(&rxnet->call_lock); - write_lock(&rxnet->call_lock); + while (!list_empty(&rxnet->calls)) { + call = list_entry(rxnet->calls.next, + struct rxrpc_call, link); + _debug("Zapping call %p", call); - while (!list_empty(&rxnet->calls)) { - call = list_entry(rxnet->calls.next, struct rxrpc_call, link); - _debug("Zapping call %p", call); + rxrpc_see_call(call); + list_del_init(&call->link); - rxrpc_see_call(call); - list_del_init(&call->link); + pr_err("Call %p still in use (%d,%s,%lx,%lx)!\n", + call, atomic_read(&call->usage), + rxrpc_call_states[call->state], + call->flags, call->events); - pr_err("Call %p still in use (%d,%s,%lx,%lx)!\n", - call, atomic_read(&call->usage), - rxrpc_call_states[call->state], - call->flags, call->events); + write_unlock(&rxnet->call_lock); + cond_resched(); + write_lock(&rxnet->call_lock); + } write_unlock(&rxnet->call_lock); - cond_resched(); - write_lock(&rxnet->call_lock); } - - write_unlock(&rxnet->call_lock); } |