From: Andrew Perepechko <c17827@cray.com>
Date: Fri, 14 Feb 2020 02:20:09 +0000 (+0300)
Subject: LU-13294 libcfs: incorrect rotor behaviour
X-Git-Tag: 2.12.5-RC1~52
X-Git-Url: https://git.whamcloud.com/gitweb?a=commitdiff_plain;h=4f704583cd561a7b6ce38c032188a6b23d9faf38;p=fs%2Flustre-release.git

LU-13294 libcfs: incorrect rotor behaviour

Signed int cpt rotor is set to -1 on initialization.
cfs_cpt_spread_node() improperly handles this value
via "if (!rotor--)" check. The condition is never true
with negative rotor values, so for_each_node_mask()
only exits with node = MAX_NUMNODES.

kmalloc_node() attempts to determine the zonelist based
on the passed node id and maps MAX_NUMNODES to some
random pointer. Crash.

BUG: unable to handle kernel paging request at 0000000100002007
IP: [<ffffffff847c0da7>] __alloc_pages_nodemask+0x97/0x420

Lustre-change: https://review.whamcloud.com/37709
Lustre-commit: f8aa86dd1622804d81020a7dbb1116f276b340f3

Change-Id: I4df74e394bdfc2a918d66aa12e6852ff0f6738ab
Signed-off-by: Andrew Perepechko <c17827@cray.com>
Cray-bug-id: LUS-8492
Reviewed-by: Alexander Boyko <c17825@cray.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>
Reviewed-by: Alexander Zarochentsev <alexander.zarochentsev@hpe.com>
Signed-off-by: Minh Diep <mdiep@whamcloud.com>
Reviewed-on: https://review.whamcloud.com/38049
Tested-by: jenkins <devops@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: Serguei Smirnov <ssmirnov@whamcloud.com>
Reviewed-by: Oleg Drokin <green@whamcloud.com>
---

diff --git a/libcfs/include/libcfs/libcfs_cpu.h b/libcfs/include/libcfs/libcfs_cpu.h
index fb268a8..4620dcc 100644
--- a/libcfs/include/libcfs/libcfs_cpu.h
+++ b/libcfs/include/libcfs/libcfs_cpu.h
@@ -91,7 +91,7 @@ struct cfs_cpu_partition {
 	/* NUMA distance between CPTs */
 	unsigned int			*cpt_distance;
 	/* spread rotor for NUMA allocator */
-	int				 cpt_spread_rotor;
+	unsigned int			 cpt_spread_rotor;
 	/* NUMA node if cpt_nodemask is empty */
 	int				 cpt_node;
 };
@@ -101,7 +101,7 @@ struct cfs_cpu_partition {
 struct cfs_cpt_table {
 #ifdef CONFIG_SMP
 	/* spread rotor for NUMA allocator */
-	int				 ctb_spread_rotor;
+	unsigned int			 ctb_spread_rotor;
 	/* maximum NUMA distance between all nodes in table */
 	unsigned int			 ctb_distance;
 	/* partitions tables */
diff --git a/libcfs/libcfs/libcfs_cpu.c b/libcfs/libcfs/libcfs_cpu.c
index 3ecd517..58bda9c 100644
--- a/libcfs/libcfs/libcfs_cpu.c
+++ b/libcfs/libcfs/libcfs_cpu.c
@@ -648,7 +648,7 @@ int cfs_cpt_spread_node(struct cfs_cpt_table *cptab, int cpt)
 {
 	nodemask_t *mask;
 	int weight;
-	int rotor;
+	unsigned int rotor;
 	int node = 0;
 
 	/* convert CPU partition ID to HW node id */