[lustre-devel] [PATCH 24/24] lustre: discard TCD_MAX_TYPES
NeilBrown
neilb at suse.com
Wed Jun 20 21:28:39 PDT 2018
As well as CFS_TCD_TYPE_CNT we have TCD_MAX_TYPES which has a larger
value but a similar meaning. Discard it and just use
CFS_TCD_TYPE_CNT.
Two places relied on the fact that TCD_MAX_TYPES was larger and so
there would be NULLs at the end of the array. Change
them to check the array size properly.
Signed-off-by: NeilBrown <neilb at suse.com>
---
Thanks for testing James!
I found two problems.
1/ I had
- for (i = 0; cfs_trace_data[i] && i < CFS_TCD_TYPE_CNT; i++) {
instead of
+ for (i = 0; i < CFS_TCD_TYPE_CNT && cfs_trace_data[i]; i++) {
So it could dereference beyond the end of an array. I don't this was
the problem.
2/ I hadn't changed
- for (i = 0; cfs_trace_data[i]; i++) \
to
+ for (i = 0; i < CFS_TCD_TYPE_CNT && cfs_trace_data[i]; i++) \
so if cfs_trace_data[4] was non NULL, bad things could happen.
I suspect this is what happened to you.
Thanks,
NeilBrown
drivers/staging/lustre/lnet/libcfs/tracefile.c | 8 ++++----
drivers/staging/lustre/lnet/libcfs/tracefile.h | 5 ++---
2 files changed, 6 insertions(+), 7 deletions(-)
diff --git a/drivers/staging/lustre/lnet/libcfs/tracefile.c b/drivers/staging/lustre/lnet/libcfs/tracefile.c
index cdef67391a72..cc399d580444 100644
--- a/drivers/staging/lustre/lnet/libcfs/tracefile.c
+++ b/drivers/staging/lustre/lnet/libcfs/tracefile.c
@@ -50,7 +50,7 @@
#include "tracefile.h"
/* XXX move things up to the top, comment */
-union cfs_trace_data_union (*cfs_trace_data[TCD_MAX_TYPES])[NR_CPUS] __cacheline_aligned;
+union cfs_trace_data_union (*cfs_trace_data[CFS_TCD_TYPE_CNT])[NR_CPUS] __cacheline_aligned;
char cfs_tracefile[TRACEFILE_NAME_SIZE];
long long cfs_tracefile_size = CFS_TRACEFILE_SIZE;
@@ -145,8 +145,8 @@ void cfs_trace_unlock_tcd(struct cfs_trace_cpu_data *tcd, int walking)
spin_unlock(&tcd->tcd_lock);
}
-#define cfs_tcd_for_each_type_lock(tcd, i, cpu) \
- for (i = 0; cfs_trace_data[i] && \
+#define cfs_tcd_for_each_type_lock(tcd, i, cpu) \
+ for (i = 0; i < CFS_TCD_TYPE_CNT && cfs_trace_data[i] && \
(tcd = &(*cfs_trace_data[i])[cpu].tcd) && \
cfs_trace_lock_tcd(tcd, 1); cfs_trace_unlock_tcd(tcd, 1), i++)
@@ -1381,7 +1381,7 @@ static void cfs_trace_cleanup(void)
cfs_trace_console_buffers[i][j] = NULL;
}
- for (i = 0; cfs_trace_data[i]; i++) {
+ for (i = 0; i < CFS_TCD_TYPE_CNT && cfs_trace_data[i]; i++) {
kfree(cfs_trace_data[i]);
cfs_trace_data[i] = NULL;
}
diff --git a/drivers/staging/lustre/lnet/libcfs/tracefile.h b/drivers/staging/lustre/lnet/libcfs/tracefile.h
index 23faecf886c1..87b00fc70b70 100644
--- a/drivers/staging/lustre/lnet/libcfs/tracefile.h
+++ b/drivers/staging/lustre/lnet/libcfs/tracefile.h
@@ -184,11 +184,10 @@ union cfs_trace_data_union {
char __pad[L1_CACHE_ALIGN(sizeof(struct cfs_trace_cpu_data))];
};
-#define TCD_MAX_TYPES 8
-extern union cfs_trace_data_union (*cfs_trace_data[TCD_MAX_TYPES])[NR_CPUS];
+extern union cfs_trace_data_union (*cfs_trace_data[CFS_TCD_TYPE_CNT])[NR_CPUS];
#define cfs_tcd_for_each(tcd, i, j) \
- for (i = 0; cfs_trace_data[i]; i++) \
+ for (i = 0; i < CFS_TCD_TYPE_CNT && cfs_trace_data[i]; i++) \
for (j = 0, ((tcd) = &(*cfs_trace_data[i])[j].tcd); \
j < num_possible_cpus(); \
j++, (tcd) = &(*cfs_trace_data[i])[j].tcd)
--
2.14.0.rc0.dirty
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