* [oracle-dtrace:v2/5.17-rc2 8/10] fs/eventpoll.c:1224:3: warning: Value stored to 'key' is never read [clang-analyzer-deadcode.DeadStores]
@ 2022-02-10 13:16 kernel test robot
0 siblings, 0 replies; only message in thread
From: kernel test robot @ 2022-02-10 13:16 UTC (permalink / raw)
To: kbuild
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CC: llvm(a)lists.linux.dev
CC: kbuild-all(a)lists.01.org
CC: linux-kernel(a)vger.kernel.org
TO: Nick Alcock <nick.alcock@oracle.com>
CC: Kris Van Hees <kris.van.hees@oracle.com>
CC: Tomas Jedlicka <tomas.jedlicka@oracle.com>
CC: Eugene Loh <eugene.loh@oracle.com>
CC: David Mc Lean <david.mclean@oracle.com>
CC: Vincent Lim <vincent.lim@oracle.com>
tree: https://github.com/oracle/dtrace-linux-kernel v2/5.17-rc2
head: a5b4aef71c1689eb071137a0d9bad70c4a0a3472
commit: c6e92f354335ab7bbcec46ccbc9fc81ae123900a [8/10] waitfd: new syscall implementing waitpid() over fds
:::::: branch date: 3 days ago
:::::: commit date: 3 days ago
config: x86_64-randconfig-c007 (https://download.01.org/0day-ci/archive/20220210/202202102101.ROZp3MW9-lkp(a)intel.com/config)
compiler: clang version 15.0.0 (https://github.com/llvm/llvm-project e8bff9ae54a55b4dbfeb6ba55f723abbd81bf494)
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/oracle/dtrace-linux-kernel/commit/c6e92f354335ab7bbcec46ccbc9fc81ae123900a
git remote add oracle-dtrace https://github.com/oracle/dtrace-linux-kernel
git fetch --no-tags oracle-dtrace v2/5.17-rc2
git checkout c6e92f354335ab7bbcec46ccbc9fc81ae123900a
# save the config file to linux build tree
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=clang make.cross ARCH=x86_64 clang-analyzer
If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>
clang-analyzer warnings: (new ones prefixed by >>)
^~~~~
fs/gfs2/dir.c:2170:2: note: Taking false branch
if (!dent) {
^
fs/gfs2/dir.c:2177:6: note: Calling 'IS_ERR'
if (IS_ERR(dent))
^~~~~~~~~~~~
include/linux/err.h:36:9: note: Assuming the condition is false
return IS_ERR_VALUE((unsigned long)ptr);
^
include/linux/err.h:22:34: note: expanded from macro 'IS_ERR_VALUE'
#define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO)
~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:78:42: note: expanded from macro 'unlikely'
# define unlikely(x) __builtin_expect(!!(x), 0)
^
include/linux/err.h:36:2: note: Returning zero, which participates in a condition later
return IS_ERR_VALUE((unsigned long)ptr);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/gfs2/dir.c:2177:6: note: Returning from 'IS_ERR'
if (IS_ERR(dent))
^~~~~~~~~~~~
fs/gfs2/dir.c:2177:2: note: Taking false branch
if (IS_ERR(dent))
^
fs/gfs2/dir.c:2180:6: note: Assuming field 'save_loc' is not equal to 0
if (da->save_loc) {
^~~~~~~~~~~~
fs/gfs2/dir.c:2180:2: note: Taking true branch
if (da->save_loc) {
^
fs/gfs2/dir.c:2181:10: note: Assigned value is garbage or undefined
da->bh = bh;
^ ~~
fs/gfs2/dir.c:2184:3: warning: 1st function call argument is an uninitialized value [clang-analyzer-core.CallAndMessage]
brelse(bh);
^ ~~
fs/gfs2/dir.c:2163:2: note: 'bh' declared without an initial value
struct buffer_head *bh;
^~~~~~~~~~~~~~~~~~~~~~
fs/gfs2/dir.c:2169:9: note: Calling 'gfs2_dirent_search'
dent = gfs2_dirent_search(inode, name, gfs2_dirent_find_space, &bh);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/gfs2/dir.c:815:6: note: Assuming the condition is false
if (ip->i_diskflags & GFS2_DIF_EXHASH) {
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/gfs2/dir.c:815:2: note: Taking false branch
if (ip->i_diskflags & GFS2_DIF_EXHASH) {
^
fs/gfs2/dir.c:848:6: note: Assuming 'error' is not equal to 0
if (error)
^~~~~
fs/gfs2/dir.c:848:2: note: Taking true branch
if (error)
^
fs/gfs2/dir.c:849:3: note: Returning without writing to '*pbh'
return ERR_PTR(error);
^
fs/gfs2/dir.c:2169:9: note: Returning from 'gfs2_dirent_search'
dent = gfs2_dirent_search(inode, name, gfs2_dirent_find_space, &bh);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/gfs2/dir.c:2170:6: note: Assuming 'dent' is non-null
if (!dent) {
^~~~~
fs/gfs2/dir.c:2170:2: note: Taking false branch
if (!dent) {
^
fs/gfs2/dir.c:2177:6: note: Calling 'IS_ERR'
if (IS_ERR(dent))
^~~~~~~~~~~~
include/linux/err.h:36:9: note: Assuming the condition is false
return IS_ERR_VALUE((unsigned long)ptr);
^
include/linux/err.h:22:34: note: expanded from macro 'IS_ERR_VALUE'
#define IS_ERR_VALUE(x) unlikely((unsigned long)(void *)(x) >= (unsigned long)-MAX_ERRNO)
~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
include/linux/compiler.h:78:42: note: expanded from macro 'unlikely'
# define unlikely(x) __builtin_expect(!!(x), 0)
^
include/linux/err.h:36:2: note: Returning zero, which participates in a condition later
return IS_ERR_VALUE((unsigned long)ptr);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/gfs2/dir.c:2177:6: note: Returning from 'IS_ERR'
if (IS_ERR(dent))
^~~~~~~~~~~~
fs/gfs2/dir.c:2177:2: note: Taking false branch
if (IS_ERR(dent))
^
fs/gfs2/dir.c:2180:6: note: Assuming field 'save_loc' is 0
if (da->save_loc) {
^~~~~~~~~~~~
fs/gfs2/dir.c:2180:2: note: Taking false branch
if (da->save_loc) {
^
fs/gfs2/dir.c:2184:3: note: 1st function call argument is an uninitialized value
brelse(bh);
^ ~~
Suppressed 6 warnings (6 in non-user code).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
9 warnings generated.
>> fs/eventpoll.c:1224:3: warning: Value stored to 'key' is never read [clang-analyzer-deadcode.DeadStores]
key = (void *)epi->fixed_event;
^ ~~~~~~~~~~~~~~~~~~~~~~~~
fs/eventpoll.c:1224:3: note: Value stored to 'key' is never read
key = (void *)epi->fixed_event;
^ ~~~~~~~~~~~~~~~~~~~~~~~~
Suppressed 8 warnings (8 in non-user code).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
4 warnings generated.
Suppressed 4 warnings (4 in non-user code).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
4 warnings generated.
Suppressed 4 warnings (4 in non-user code).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
4 warnings generated.
Suppressed 4 warnings (4 in non-user code).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
5 warnings generated.
fs/eventfd.c:285:8: warning: Value stored to 'res' is never read [clang-analyzer-deadcode.DeadStores]
for (res = 0;;) {
^ ~
fs/eventfd.c:285:8: note: Value stored to 'res' is never read
for (res = 0;;) {
^ ~
Suppressed 4 warnings (4 in non-user code).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
5 warnings generated.
fs/userfaultfd.c:986:14: warning: Access to field 'flags' results in a dereference of a null pointer (loaded from variable 'new') [clang-analyzer-core.NullDereference]
O_RDWR | (new->flags & UFFD_SHARED_FCNTL_FLAGS), inode);
^
fs/userfaultfd.c:1169:6: note: Assuming the condition is false
if (!userfaultfd_is_initialized(ctx))
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/userfaultfd.c:1169:2: note: Taking false branch
if (!userfaultfd_is_initialized(ctx))
^
fs/userfaultfd.c:1172:2: note: Loop condition is true. Entering loop body
for (;;) {
^
fs/userfaultfd.c:1173:7: note: Assuming the condition is false
if (count < sizeof(msg))
^~~~~~~~~~~~~~~~~~~
fs/userfaultfd.c:1173:3: note: Taking false branch
if (count < sizeof(msg))
^
fs/userfaultfd.c:1175:10: note: Calling 'userfaultfd_ctx_read'
_ret = userfaultfd_ctx_read(ctx, no_wait, &msg, inode);
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/userfaultfd.c:1009:2: note: 'fork_nctx' initialized to a null pointer value
struct userfaultfd_ctx *fork_nctx = NULL;
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/userfaultfd.c:1014:2: note: Loop condition is true. Entering loop body
for (;;) {
^
fs/userfaultfd.c:1015:3: note: Taking false branch
set_current_state(TASK_INTERRUPTIBLE);
^
include/linux/sched.h:210:3: note: expanded from macro 'set_current_state'
debug_normal_state_change((state_value)); \
^
include/linux/sched.h:137:3: note: expanded from macro 'debug_normal_state_change'
WARN_ON_ONCE(is_special_task_state(state_value)); \
^
include/asm-generic/bug.h:105:2: note: expanded from macro 'WARN_ON_ONCE'
if (unlikely(__ret_warn_on)) \
^
fs/userfaultfd.c:1015:3: note: Loop condition is false. Exiting loop
set_current_state(TASK_INTERRUPTIBLE);
^
include/linux/sched.h:210:3: note: expanded from macro 'set_current_state'
debug_normal_state_change((state_value)); \
^
include/linux/sched.h:136:2: note: expanded from macro 'debug_normal_state_change'
do { \
^
fs/userfaultfd.c:1015:3: note: Loop condition is false. Exiting loop
set_current_state(TASK_INTERRUPTIBLE);
^
include/linux/sched.h:211:3: note: expanded from macro 'set_current_state'
smp_store_mb(current->__state, (state_value)); \
^
include/asm-generic/barrier.h:152:40: note: expanded from macro 'smp_store_mb'
#define smp_store_mb(var, value) do { kcsan_mb(); __smp_store_mb(var, value); } while (0)
^
include/linux/kcsan-checks.h:264:20: note: expanded from macro 'kcsan_mb'
#define kcsan_mb() do { } while (0)
^
fs/userfaultfd.c:1015:3: note: Loop condition is false. Exiting loop
set_current_state(TASK_INTERRUPTIBLE);
^
include/linux/sched.h:211:3: note: expanded from macro 'set_current_state'
smp_store_mb(current->__state, (state_value)); \
^
include/asm-generic/barrier.h:152:52: note: expanded from macro 'smp_store_mb'
#define smp_store_mb(var, value) do { kcsan_mb(); __smp_store_mb(var, value); } while (0)
^
arch/x86/include/asm/barrier.h:61:47: note: expanded from macro '__smp_store_mb'
#define __smp_store_mb(var, value) do { (void)xchg(&var, value); } while (0)
^
include/linux/atomic/atomic-instrumented.h:1884:2: note: expanded from macro 'xchg'
kcsan_mb(); \
vim +/key +1224 fs/eventpoll.c
a218cc4914209a Roman Penyaev 2019-03-07 1118
^1da177e4c3f41 Linus Torvalds 2005-04-16 1119 /*
7699acd1341c63 Davide Libenzi 2007-05-10 1120 * This is the callback that is passed to the wait queue wakeup
bf6a41db7726e6 Daniel Baluta 2011-01-30 1121 * mechanism. It is called by the stored file descriptors when they
7699acd1341c63 Davide Libenzi 2007-05-10 1122 * have events to report.
a218cc4914209a Roman Penyaev 2019-03-07 1123 *
a6c67fee9cf095 Randy Dunlap 2021-03-01 1124 * This callback takes a read lock in order not to contend with concurrent
a6c67fee9cf095 Randy Dunlap 2021-03-01 1125 * events from another file descriptor, thus all modifications to ->rdllist
a218cc4914209a Roman Penyaev 2019-03-07 1126 * or ->ovflist are lockless. Read lock is paired with the write lock from
a218cc4914209a Roman Penyaev 2019-03-07 1127 * ep_scan_ready_list(), which stops all list modifications and guarantees
a218cc4914209a Roman Penyaev 2019-03-07 1128 * that lists state is seen correctly.
a218cc4914209a Roman Penyaev 2019-03-07 1129 *
a218cc4914209a Roman Penyaev 2019-03-07 1130 * Another thing worth to mention is that ep_poll_callback() can be called
a218cc4914209a Roman Penyaev 2019-03-07 1131 * concurrently for the same @epi from different CPUs if poll table was inited
a218cc4914209a Roman Penyaev 2019-03-07 1132 * with several wait queues entries. Plural wakeup from different CPUs of a
a218cc4914209a Roman Penyaev 2019-03-07 1133 * single wait queue is serialized by wq.lock, but the case when multiple wait
a218cc4914209a Roman Penyaev 2019-03-07 1134 * queues are used should be detected accordingly. This is detected using
a218cc4914209a Roman Penyaev 2019-03-07 1135 * cmpxchg() operation.
^1da177e4c3f41 Linus Torvalds 2005-04-16 1136 */
ac6424b981bce1 Ingo Molnar 2017-06-20 1137 static int ep_poll_callback(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
^1da177e4c3f41 Linus Torvalds 2005-04-16 1138 {
7699acd1341c63 Davide Libenzi 2007-05-10 1139 int pwake = 0;
7699acd1341c63 Davide Libenzi 2007-05-10 1140 struct epitem *epi = ep_item_from_wait(wait);
7699acd1341c63 Davide Libenzi 2007-05-10 1141 struct eventpoll *ep = epi->ep;
3ad6f93e98d6df Al Viro 2017-07-03 1142 __poll_t pollflags = key_to_poll(key);
a218cc4914209a Roman Penyaev 2019-03-07 1143 unsigned long flags;
df0108c5da561c Jason Baron 2016-01-20 1144 int ewake = 0;
^1da177e4c3f41 Linus Torvalds 2005-04-16 1145
a218cc4914209a Roman Penyaev 2019-03-07 1146 read_lock_irqsave(&ep->lock, flags);
^1da177e4c3f41 Linus Torvalds 2005-04-16 1147
bf3b9f6372c45b Sridhar Samudrala 2017-03-24 1148 ep_set_busy_poll_napi_id(epi);
bf3b9f6372c45b Sridhar Samudrala 2017-03-24 1149
^1da177e4c3f41 Linus Torvalds 2005-04-16 1150 /*
7699acd1341c63 Davide Libenzi 2007-05-10 1151 * If the event mask does not contain any poll(2) event, we consider the
7699acd1341c63 Davide Libenzi 2007-05-10 1152 * descriptor to be disabled. This condition is likely the effect of the
7699acd1341c63 Davide Libenzi 2007-05-10 1153 * EPOLLONESHOT bit that disables the descriptor when an event is received,
7699acd1341c63 Davide Libenzi 2007-05-10 1154 * until the next EPOLL_CTL_MOD will be issued.
^1da177e4c3f41 Linus Torvalds 2005-04-16 1155 */
7699acd1341c63 Davide Libenzi 2007-05-10 1156 if (!(epi->event.events & ~EP_PRIVATE_BITS))
d47de16c722196 Davide Libenzi 2007-05-15 1157 goto out_unlock;
d47de16c722196 Davide Libenzi 2007-05-15 1158
2dfa4eeab0fc7e Davide Libenzi 2009-03-31 1159 /*
2dfa4eeab0fc7e Davide Libenzi 2009-03-31 1160 * Check the events coming with the callback. At this stage, not
2dfa4eeab0fc7e Davide Libenzi 2009-03-31 1161 * every device reports the events in the "key" parameter of the
2dfa4eeab0fc7e Davide Libenzi 2009-03-31 1162 * callback. We need to be able to handle both cases here, hence the
2dfa4eeab0fc7e Davide Libenzi 2009-03-31 1163 * test for "key" != NULL before the event match test.
2dfa4eeab0fc7e Davide Libenzi 2009-03-31 1164 */
3ad6f93e98d6df Al Viro 2017-07-03 1165 if (pollflags && !(pollflags & epi->event.events))
2dfa4eeab0fc7e Davide Libenzi 2009-03-31 1166 goto out_unlock;
2dfa4eeab0fc7e Davide Libenzi 2009-03-31 1167
d47de16c722196 Davide Libenzi 2007-05-15 1168 /*
bf6a41db7726e6 Daniel Baluta 2011-01-30 1169 * If we are transferring events to userspace, we can hold no locks
d47de16c722196 Davide Libenzi 2007-05-15 1170 * (because we're accessing user memory, and because of linux f_op->poll()
bf6a41db7726e6 Daniel Baluta 2011-01-30 1171 * semantics). All the events that happen during that period of time are
d47de16c722196 Davide Libenzi 2007-05-15 1172 * chained in ep->ovflist and requeued later on.
d47de16c722196 Davide Libenzi 2007-05-15 1173 */
c5a282e9635e9c Davidlohr Bueso 2019-01-03 1174 if (READ_ONCE(ep->ovflist) != EP_UNACTIVE_PTR) {
0c54a6a44bf3d4 Khazhismel Kumykov 2020-05-07 1175 if (chain_epi_lockless(epi))
c3e320b61581ef Roman Penyaev 2019-03-07 1176 ep_pm_stay_awake_rcu(epi);
0c54a6a44bf3d4 Khazhismel Kumykov 2020-05-07 1177 } else if (!ep_is_linked(epi)) {
0c54a6a44bf3d4 Khazhismel Kumykov 2020-05-07 1178 /* In the usual case, add event to ready list. */
0c54a6a44bf3d4 Khazhismel Kumykov 2020-05-07 1179 if (list_add_tail_lockless(&epi->rdllink, &ep->rdllist))
eea1d585917c53 Eric Wong 2013-04-30 1180 ep_pm_stay_awake_rcu(epi);
4d7e30d98939a0 Arve Hjønnevåg 2012-05-01 1181 }
7699acd1341c63 Davide Libenzi 2007-05-10 1182
7699acd1341c63 Davide Libenzi 2007-05-10 1183 /*
7699acd1341c63 Davide Libenzi 2007-05-10 1184 * Wake up ( if active ) both the eventpoll wait list and the ->poll()
7699acd1341c63 Davide Libenzi 2007-05-10 1185 * wait list.
7699acd1341c63 Davide Libenzi 2007-05-10 1186 */
df0108c5da561c Jason Baron 2016-01-20 1187 if (waitqueue_active(&ep->wq)) {
b6a515c8a0f6c2 Jason Baron 2016-02-05 1188 if ((epi->event.events & EPOLLEXCLUSIVE) &&
3ad6f93e98d6df Al Viro 2017-07-03 1189 !(pollflags & POLLFREE)) {
3ad6f93e98d6df Al Viro 2017-07-03 1190 switch (pollflags & EPOLLINOUT_BITS) {
a9a08845e9acbd Linus Torvalds 2018-02-11 1191 case EPOLLIN:
a9a08845e9acbd Linus Torvalds 2018-02-11 1192 if (epi->event.events & EPOLLIN)
b6a515c8a0f6c2 Jason Baron 2016-02-05 1193 ewake = 1;
b6a515c8a0f6c2 Jason Baron 2016-02-05 1194 break;
a9a08845e9acbd Linus Torvalds 2018-02-11 1195 case EPOLLOUT:
a9a08845e9acbd Linus Torvalds 2018-02-11 1196 if (epi->event.events & EPOLLOUT)
b6a515c8a0f6c2 Jason Baron 2016-02-05 1197 ewake = 1;
b6a515c8a0f6c2 Jason Baron 2016-02-05 1198 break;
b6a515c8a0f6c2 Jason Baron 2016-02-05 1199 case 0:
df0108c5da561c Jason Baron 2016-01-20 1200 ewake = 1;
b6a515c8a0f6c2 Jason Baron 2016-02-05 1201 break;
b6a515c8a0f6c2 Jason Baron 2016-02-05 1202 }
b6a515c8a0f6c2 Jason Baron 2016-02-05 1203 }
a218cc4914209a Roman Penyaev 2019-03-07 1204 wake_up(&ep->wq);
df0108c5da561c Jason Baron 2016-01-20 1205 }
7699acd1341c63 Davide Libenzi 2007-05-10 1206 if (waitqueue_active(&ep->poll_wait))
7699acd1341c63 Davide Libenzi 2007-05-10 1207 pwake++;
^1da177e4c3f41 Linus Torvalds 2005-04-16 1208
d47de16c722196 Davide Libenzi 2007-05-15 1209 out_unlock:
a218cc4914209a Roman Penyaev 2019-03-07 1210 read_unlock_irqrestore(&ep->lock, flags);
7699acd1341c63 Davide Libenzi 2007-05-10 1211
7699acd1341c63 Davide Libenzi 2007-05-10 1212 /* We have to call this outside the lock */
7699acd1341c63 Davide Libenzi 2007-05-10 1213 if (pwake)
efcdd350d1f8a9 Jason Baron 2020-04-06 1214 ep_poll_safewake(ep, epi);
7699acd1341c63 Davide Libenzi 2007-05-10 1215
138e4ad67afd5c Oleg Nesterov 2017-09-01 1216 if (!(epi->event.events & EPOLLEXCLUSIVE))
138e4ad67afd5c Oleg Nesterov 2017-09-01 1217 ewake = 1;
138e4ad67afd5c Oleg Nesterov 2017-09-01 1218
c6e92f354335ab Nick Alcock 2018-11-14 1219 /*
c6e92f354335ab Nick Alcock 2018-11-14 1220 * If this fd type has a hardwired event which should override the key
c6e92f354335ab Nick Alcock 2018-11-14 1221 * (e.g. if it is waiting on a non-file waitqueue), jam it in here.
c6e92f354335ab Nick Alcock 2018-11-14 1222 */
c6e92f354335ab Nick Alcock 2018-11-14 1223 if (epi->fixed_event)
c6e92f354335ab Nick Alcock 2018-11-14 @1224 key = (void *)epi->fixed_event;
c6e92f354335ab Nick Alcock 2018-11-14 1225
3ad6f93e98d6df Al Viro 2017-07-03 1226 if (pollflags & POLLFREE) {
138e4ad67afd5c Oleg Nesterov 2017-09-01 1227 /*
138e4ad67afd5c Oleg Nesterov 2017-09-01 1228 * If we race with ep_remove_wait_queue() it can miss
138e4ad67afd5c Oleg Nesterov 2017-09-01 1229 * ->whead = NULL and do another remove_wait_queue() after
138e4ad67afd5c Oleg Nesterov 2017-09-01 1230 * us, so we can't use __remove_wait_queue().
138e4ad67afd5c Oleg Nesterov 2017-09-01 1231 */
138e4ad67afd5c Oleg Nesterov 2017-09-01 1232 list_del_init(&wait->entry);
138e4ad67afd5c Oleg Nesterov 2017-09-01 1233 /*
138e4ad67afd5c Oleg Nesterov 2017-09-01 1234 * ->whead != NULL protects us from the race with ep_free()
138e4ad67afd5c Oleg Nesterov 2017-09-01 1235 * or ep_remove(), ep_remove_wait_queue() takes whead->lock
138e4ad67afd5c Oleg Nesterov 2017-09-01 1236 * held by the caller. Once we nullify it, nothing protects
138e4ad67afd5c Oleg Nesterov 2017-09-01 1237 * ep/epi or even wait.
138e4ad67afd5c Oleg Nesterov 2017-09-01 1238 */
138e4ad67afd5c Oleg Nesterov 2017-09-01 1239 smp_store_release(&ep_pwq_from_wait(wait)->whead, NULL);
138e4ad67afd5c Oleg Nesterov 2017-09-01 1240 }
df0108c5da561c Jason Baron 2016-01-20 1241
138e4ad67afd5c Oleg Nesterov 2017-09-01 1242 return ewake;
7699acd1341c63 Davide Libenzi 2007-05-10 1243 }
^1da177e4c3f41 Linus Torvalds 2005-04-16 1244
---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all(a)lists.01.org
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2022-02-10 13:16 [oracle-dtrace:v2/5.17-rc2 8/10] fs/eventpoll.c:1224:3: warning: Value stored to 'key' is never read [clang-analyzer-deadcode.DeadStores] kernel test robot
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