* [Ocfs2-devel] [bug report] ocfs2/cluster: Pin/unpin o2hb regions
@ 2022-01-19 11:29 Dan Carpenter via Ocfs2-devel
2022-01-20 2:13 ` Joseph Qi via Ocfs2-devel
0 siblings, 1 reply; 3+ messages in thread
From: Dan Carpenter via Ocfs2-devel @ 2022-01-19 11:29 UTC (permalink / raw)
To: ocfs2-devel
Hello OCFS2 developers,
The patch 58a3158a5d17: "ocfs2/cluster: Pin/unpin o2hb regions" from
Dec 14, 2010, leads to the following Smatch static checker warning:
./include/linux/fs.h:777 inode_lock()
warn: sleeping in atomic context
The call tree is:
o2hb_heartbeat_group_drop_item() <- disables preempt
o2hb_region_inc_user() <- disables preempt
-> o2hb_region_pin()
-> o2nm_depend_item()
-> configfs_depend_item()
-> inode_lock()
fs/ocfs2/cluster/heartbeat.c
2265 static int o2hb_region_pin(const char *region_uuid)
2266 {
2267 int ret = 0, found = 0;
2268 struct o2hb_region *reg;
2269 char *uuid;
2270
2271 assert_spin_locked(&o2hb_live_lock);
^^^^^^^^^^^^^^^^^^
This code is holding a spin lock.
2272
2273 list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
2274 if (reg->hr_item_dropped)
2275 continue;
2276
2277 uuid = config_item_name(®->hr_item);
2278
2279 /* local heartbeat */
2280 if (region_uuid) {
2281 if (strcmp(region_uuid, uuid))
2282 continue;
2283 found = 1;
2284 }
2285
2286 if (reg->hr_item_pinned || reg->hr_item_dropped)
2287 goto skip_pin;
2288
2289 /* Ignore ENOENT only for local hb (userdlm domain) */
2290 ret = o2nm_depend_item(®->hr_item);
^^^^^^^^^^^^^^^^
The o2nm_depend_item() fucntion cannot succeed without taking a mutex.
2291 if (!ret) {
2292 mlog(ML_CLUSTER, "Pin region %s\n", uuid);
2293 reg->hr_item_pinned = 1;
2294 } else {
2295 if (ret == -ENOENT && found)
2296 ret = 0;
2297 else {
2298 mlog(ML_ERROR, "Pin region %s fails with %d\n",
2299 uuid, ret);
2300 break;
2301 }
2302 }
2303 skip_pin:
2304 if (found)
2305 break;
2306 }
2307
2308 return ret;
2309 }
regards,
dan carpenter
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^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [Ocfs2-devel] [bug report] ocfs2/cluster: Pin/unpin o2hb regions
2022-01-19 11:29 [Ocfs2-devel] [bug report] ocfs2/cluster: Pin/unpin o2hb regions Dan Carpenter via Ocfs2-devel
@ 2022-01-20 2:13 ` Joseph Qi via Ocfs2-devel
0 siblings, 0 replies; 3+ messages in thread
From: Joseph Qi via Ocfs2-devel @ 2022-01-20 2:13 UTC (permalink / raw)
To: Dan Carpenter, ocfs2-devel
Hi Dan Carpenter,
Thanks for the reporting.
It seems the bug truly exists, but currently I don't have an easy way to
fix it. I'll look it deeply later.
Thanks，
Joseph
On 1/19/22 7:29 PM, Dan Carpenter via Ocfs2-devel wrote:
> Hello OCFS2 developers,
>
> The patch 58a3158a5d17: "ocfs2/cluster: Pin/unpin o2hb regions" from
> Dec 14, 2010, leads to the following Smatch static checker warning:
>
> ./include/linux/fs.h:777 inode_lock()
> warn: sleeping in atomic context
>
> The call tree is:
>
> o2hb_heartbeat_group_drop_item() <- disables preempt
> o2hb_region_inc_user() <- disables preempt
> -> o2hb_region_pin()
> -> o2nm_depend_item()
> -> configfs_depend_item()
> -> inode_lock()
>
> fs/ocfs2/cluster/heartbeat.c
> 2265 static int o2hb_region_pin(const char *region_uuid)
> 2266 {
> 2267 int ret = 0, found = 0;
> 2268 struct o2hb_region *reg;
> 2269 char *uuid;
> 2270
> 2271 assert_spin_locked(&o2hb_live_lock);
> ^^^^^^^^^^^^^^^^^^
>
> This code is holding a spin lock.
>
> 2272
> 2273 list_for_each_entry(reg, &o2hb_all_regions, hr_all_item) {
> 2274 if (reg->hr_item_dropped)
> 2275 continue;
> 2276
> 2277 uuid = config_item_name(®->hr_item);
> 2278
> 2279 /* local heartbeat */
> 2280 if (region_uuid) {
> 2281 if (strcmp(region_uuid, uuid))
> 2282 continue;
> 2283 found = 1;
> 2284 }
> 2285
> 2286 if (reg->hr_item_pinned || reg->hr_item_dropped)
> 2287 goto skip_pin;
> 2288
> 2289 /* Ignore ENOENT only for local hb (userdlm domain) */
> 2290 ret = o2nm_depend_item(®->hr_item);
> ^^^^^^^^^^^^^^^^
> The o2nm_depend_item() fucntion cannot succeed without taking a mutex.
>
> 2291 if (!ret) {
> 2292 mlog(ML_CLUSTER, "Pin region %s\n", uuid);
> 2293 reg->hr_item_pinned = 1;
> 2294 } else {
> 2295 if (ret == -ENOENT && found)
> 2296 ret = 0;
> 2297 else {
> 2298 mlog(ML_ERROR, "Pin region %s fails with %d\n",
> 2299 uuid, ret);
> 2300 break;
> 2301 }
> 2302 }
> 2303 skip_pin:
> 2304 if (found)
> 2305 break;
> 2306 }
> 2307
> 2308 return ret;
> 2309 }
>
> regards,
> dan carpenter
>
> _______________________________________________
> Ocfs2-devel mailing list
> Ocfs2-devel@oss.oracle.com
> https://oss.oracle.com/mailman/listinfo/ocfs2-devel
_______________________________________________
Ocfs2-devel mailing list
Ocfs2-devel@oss.oracle.com
https://oss.oracle.com/mailman/listinfo/ocfs2-devel
^ permalink raw reply [flat|nested] 3+ messages in thread
* [Ocfs2-devel] [bug report] ocfs2/cluster: Pin/unpin o2hb regions
@ 2023-06-06 8:22 Dan Carpenter via Ocfs2-devel
0 siblings, 0 replies; 3+ messages in thread
From: Dan Carpenter via Ocfs2-devel @ 2023-06-06 8:22 UTC (permalink / raw)
To: ocfs2-devel
[ This is ancient code. - dan ]
fs/fs_context.c
168 {
169 int ret;
170
171 struct fs_parameter param = {
172 .key = key,
173 .type = fs_value_is_flag,
174 .size = v_size,
175 };
176
177 if (value) {
--> 178 param.string = kmemdup_nul(value, v_size, GFP_KERNEL);
^^^^^^^^^^
Sleeping
179 if (!param.string)
180 return -ENOMEM;
181 param.type = fs_value_is_string;
182 }
183
184 ret = vfs_parse_fs_param(fc, ¶m);
185 kfree(param.string);
186 return ret;
187 }
There are a couple OCFS functions which call this sleeping function
while holding a spinlock.
o2hb_heartbeat_group_drop_item() <- disables preempt
o2hb_region_inc_user() <- disables preempt
-> o2hb_region_pin()
-> o2nm_depend_item()
-> configfs_depend_item()
-> configfs_pin_fs()
-> simple_pin_fs()
-> vfs_kern_mount()
-> vfs_parse_fs_string()
fs/ocfs2/cluster/heartbeat.c
2338 static int o2hb_region_inc_user(const char *region_uuid)
2339 {
2340 int ret = 0;
2341
2342 spin_lock(&o2hb_live_lock);
Lock.
2343
2344 /* local heartbeat */
2345 if (!o2hb_global_heartbeat_active()) {
2346 ret = o2hb_region_pin(region_uuid);
This function starts the call tree to vfs_parse_fs_string().
2347 goto unlock;
2348 }
2349
regards,
dan carpenter
_______________________________________________
Ocfs2-devel mailing list
Ocfs2-devel@oss.oracle.com
https://oss.oracle.com/mailman/listinfo/ocfs2-devel
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-01-19 11:29 [Ocfs2-devel] [bug report] ocfs2/cluster: Pin/unpin o2hb regions Dan Carpenter via Ocfs2-devel
2022-01-20 2:13 ` Joseph Qi via Ocfs2-devel
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