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b13023421b
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:
|
||
|---|---|---|
| .. | ||
| af_rxrpc.c | ||
| ar-internal.h | ||
| call_accept.c | ||
| call_event.c | ||
| call_object.c | ||
| conn_client.c | ||
| conn_event.c | ||
| conn_object.c | ||
| conn_service.c | ||
| input.c | ||
| insecure.c | ||
| Kconfig | ||
| key.c | ||
| local_event.c | ||
| local_object.c | ||
| Makefile | ||
| misc.c | ||
| net_ns.c | ||
| output.c | ||
| peer_event.c | ||
| peer_object.c | ||
| proc.c | ||
| protocol.h | ||
| recvmsg.c | ||
| rxkad.c | ||
| security.c | ||
| sendmsg.c | ||
| skbuff.c | ||
| sysctl.c | ||
| utils.c | ||