LU-15420 uapi: avoid gcc-11 -Werror=stringop-overread

GCC 11 warns about string and memory operations on fixed address:

In function ‘strlen’,
    inlined from ‘changelog_rec_sname’ at include/uapi/linux/lustre/lustre_user.h:1981:19,
    inlined from ‘mdd_changelog_rec_ext_rename’ at lustre/mdd/mdd_dir.c:932:2,
    inlined from ‘mdd_changelog_ns_store’ at lustre/mdd/mdd_dir.c:1061:3:
include/linux/fortify-string.h:25:33: error: ‘__builtin_strlen’
reading 1 or more bytes from a region of size 0 [-Werror=stringop-overread]
   25 | #define __underlying_strlen     __builtin_strlen

The reason is that we are looking for an address right after the end
of the chanelog record header which gcc thinks is an overrun. Rework
the code to allow us to index the memory right after the changelog
record header.

Also fix a long hidden bug in the lustre snmp code.

Lustre-change: https://review.whamcloud.com/46319
Lustre-commit: TBD (from 0ae7f1196ba14df9a2354f0803eb75eea92cb1ee)

Change-Id: I13479b9074a392330d39f01656b26f9e9a91a8ec
Signed-off-by: James Simmons <jsimmons@infradead.org>
Reviewed-on: https://review.whamcloud.com/46498
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>

diff --git a/lustre/include/uapi/linux/lustre/lustre_user.h b/lustre/include/uapi/linux/lustre/lustre_user.h
index 5d6fa40..c5ada6f 100644 (file)
--- a/lustre/include/uapi/linux/lustre/lustre_user.h
+++ b/lustre/include/uapi/linux/lustre/lustre_user.h
@@ -41,6 +41,16 @@
  *
  * @{
  */
+#ifndef __KERNEL__
+# define __USE_ISOC99  1
+# include <stdbool.h>
+# include <stdio.h> /* snprintf() */
+# include <sys/stat.h>
+
+# define __USE_GNU      1
+# define __USE_XOPEN2K8  1
+# define FILEID_LUSTRE 0x97 /* for name_to_handle_at() (and llapi_fd2fid()) */
+#endif /* !__KERNEL__ */
 
 #include <linux/fs.h>
 #include <linux/limits.h>
@@ -52,14 +62,6 @@
 #include <linux/lustre/lustre_fiemap.h>
 #include <linux/lustre/lustre_ver.h>
 
-#ifndef __KERNEL__
-# define __USE_ISOC99  1
-# include <stdbool.h>
-# include <stdio.h> /* snprintf() */
-# include <sys/stat.h>
-# define FILEID_LUSTRE 0x97 /* for name_to_handle_at() (and llapi_fd2fid()) */
-#endif /* !__KERNEL__ */
-
 #if defined(__cplusplus)
 extern "C" {
 #endif
@@ -1992,16 +1994,14 @@ static inline char *changelog_rec_name(const struct changelog_rec *rec)
                (enum changelog_rec_extra_flags)(cref & CLFE_SUPPORTED));
 }
 
-static inline __kernel_size_t changelog_rec_snamelen(const struct changelog_rec *rec)
+static inline char *changelog_rec_sname(const struct changelog_rec *rec)
 {
-       return rec->cr_namelen - strlen(changelog_rec_name(rec)) - 1;
+       return strchrnul(changelog_rec_name(rec), '\0') + 1;
 }
 
-static inline char *changelog_rec_sname(const struct changelog_rec *rec)
+static inline __kernel_size_t changelog_rec_snamelen(const struct changelog_rec *rec)
 {
-       char *cr_name = changelog_rec_name(rec);
-
-       return cr_name + strlen(cr_name) + 1;
+       return strlen(changelog_rec_sname(rec));
 }
 
 /**

diff --git a/lustre/tests/mpi/Makefile.am b/lustre/tests/mpi/Makefile.am
index d64964e..7cc95af 100644 (file)
--- a/lustre/tests/mpi/Makefile.am
+++ b/lustre/tests/mpi/Makefile.am
@@ -1,5 +1,5 @@
 # Lustre MPI test Makefile
-AM_CFLAGS := -fPIC -D_LARGEFILE64_SOURCE=1 -D_FILE_OFFSET_BITS=64
+AM_CFLAGS := -fPIC -D_GNU_SOURCE -D_LARGEFILE64_SOURCE=1 -D_FILE_OFFSET_BITS=64
 
 CC = @MPICC_WRAPPER@
 

diff --git a/snmp/lustre-snmp.c b/snmp/lustre-snmp.c
index 3d8bcbc..603d343 100644 (file)
--- a/snmp/lustre-snmp.c
+++ b/snmp/lustre-snmp.c
@@ -713,7 +713,7 @@ void deinit_lustresnmp(void) {
        /* deregister ourselves with the agent */
        unregister_mib(clusterFileSystems_variables_oid,
                       sizeof(clusterFileSystems_variables_oid)/
-                      sizeof(clusterFileSystems_variables_oid));
+                      sizeof(clusterFileSystems_variables_oid[0]));
 
        terminate_trap_handler();