From 5c11720767f70d34357d00a15ba5a0ad052c40fe Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Thu, 5 Aug 2021 15:11:24 -0400 Subject: [PATCH] SUNRPC: Fix a NULL pointer deref in trace_svc_stats_latency() Some paths through svc_process() leave rqst->rq_procinfo set to NULL, which triggers a crash if tracing happens to be enabled. Fixes: 89ff87494c6e ("SUNRPC: Display RPC procedure names instead of proc numbers") Signed-off-by: Chuck Lever --- include/linux/sunrpc/svc.h | 1 + include/trace/events/sunrpc.h | 8 ++++---- net/sunrpc/svc.c | 15 +++++++++++++++ 3 files changed, 20 insertions(+), 4 deletions(-) diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h index ab9afbf0..f0f846f 100644 --- a/include/linux/sunrpc/svc.h +++ b/include/linux/sunrpc/svc.h @@ -527,6 +527,7 @@ void svc_wake_up(struct svc_serv *); void svc_reserve(struct svc_rqst *rqstp, int space); struct svc_pool * svc_pool_for_cpu(struct svc_serv *serv, int cpu); char * svc_print_addr(struct svc_rqst *, char *, size_t); +const char * svc_proc_name(const struct svc_rqst *rqstp); int svc_encode_result_payload(struct svc_rqst *rqstp, unsigned int offset, unsigned int length); diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h index 861f199..d323f5a 100644 --- a/include/trace/events/sunrpc.h +++ b/include/trace/events/sunrpc.h @@ -1642,7 +1642,7 @@ TRACE_EVENT(svc_process, __field(u32, vers) __field(u32, proc) __string(service, name) - __string(procedure, rqst->rq_procinfo->pc_name) + __string(procedure, svc_proc_name(rqst)) __string(addr, rqst->rq_xprt ? rqst->rq_xprt->xpt_remotebuf : "(null)") ), @@ -1652,7 +1652,7 @@ TRACE_EVENT(svc_process, __entry->vers = rqst->rq_vers; __entry->proc = rqst->rq_proc; __assign_str(service, name); - __assign_str(procedure, rqst->rq_procinfo->pc_name); + __assign_str(procedure, svc_proc_name(rqst)); __assign_str(addr, rqst->rq_xprt ? rqst->rq_xprt->xpt_remotebuf : "(null)"); ), @@ -1918,7 +1918,7 @@ TRACE_EVENT(svc_stats_latency, TP_STRUCT__entry( __field(u32, xid) __field(unsigned long, execute) - __string(procedure, rqst->rq_procinfo->pc_name) + __string(procedure, svc_proc_name(rqst)) __string(addr, rqst->rq_xprt->xpt_remotebuf) ), @@ -1926,7 +1926,7 @@ TRACE_EVENT(svc_stats_latency, __entry->xid = be32_to_cpu(rqst->rq_xid); __entry->execute = ktime_to_us(ktime_sub(ktime_get(), rqst->rq_stime)); - __assign_str(procedure, rqst->rq_procinfo->pc_name); + __assign_str(procedure, svc_proc_name(rqst)); __assign_str(addr, rqst->rq_xprt->xpt_remotebuf); ), diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c index d2d412d..5aa2633 100644 --- a/net/sunrpc/svc.c +++ b/net/sunrpc/svc.c @@ -1651,6 +1651,21 @@ u32 svc_max_payload(const struct svc_rqst *rqstp) EXPORT_SYMBOL_GPL(svc_max_payload); /** + * svc_proc_name - Return RPC procedure name in string form + * @rqstp: svc_rqst to operate on + * + * Return value: + * Pointer to a NUL-terminated string + */ +const char *svc_proc_name(const struct svc_rqst *rqstp) +{ + if (rqstp && rqstp->rq_procinfo) + return rqstp->rq_procinfo->pc_name; + return "unknown"; +} + + +/** * svc_encode_result_payload - mark a range of bytes as a result payload * @rqstp: svc_rqst to operate on * @offset: payload's byte offset in rqstp->rq_res -- 2.7.4