From: Dan Carpenter <dan.carpenter@oracle.com> To: kernelfans@gmail.com Cc: linux-pm@vger.kernel.org, kexec@lists.infradead.org Subject: [bug report] PM / reboot: Eliminate race between reboot and suspend Date: Wed, 18 Nov 2020 21:59:17 +0300 [thread overview] Message-ID: <20201118185917.GA433776@mwanda> (raw) Hello Pingfan Liu, The patch 55f2503c3b69: "PM / reboot: Eliminate race between reboot and suspend" from Jul 31, 2018, leads to the following static checker warning: kernel/power/main.c:27 lock_system_sleep() warn: called with lock held. '&system_transition_mutex' kernel/reboot.c 345 346 mutex_lock(&system_transition_mutex); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The patch changed the code to take this lock. 347 switch (cmd) { 348 case LINUX_REBOOT_CMD_RESTART: 349 kernel_restart(NULL); 350 break; 351 352 case LINUX_REBOOT_CMD_CAD_ON: 353 C_A_D = 1; 354 break; 355 356 case LINUX_REBOOT_CMD_CAD_OFF: 357 C_A_D = 0; 358 break; 359 360 case LINUX_REBOOT_CMD_HALT: 361 kernel_halt(); 362 do_exit(0); 363 panic("cannot halt"); 364 365 case LINUX_REBOOT_CMD_POWER_OFF: 366 kernel_power_off(); 367 do_exit(0); 368 break; 369 370 case LINUX_REBOOT_CMD_RESTART2: 371 ret = strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1); 372 if (ret < 0) { 373 ret = -EFAULT; 374 break; 375 } 376 buffer[sizeof(buffer) - 1] = '\0'; 377 378 kernel_restart(buffer); 379 break; 380 381 #ifdef CONFIG_KEXEC_CORE 382 case LINUX_REBOOT_CMD_KEXEC: 383 ret = kernel_kexec(); ^^^^^^^^^^^^^^^^^^^^ Called with lock held. 384 break; 385 #endif But kernel_kexec() also tries to take the &system_transition_mutex so it will dead lock. kernel/kexec_core.c 1125 int kernel_kexec(void) 1126 { 1127 int error = 0; 1128 1129 if (!mutex_trylock(&kexec_mutex)) 1130 return -EBUSY; 1131 if (!kexec_image) { 1132 error = -EINVAL; 1133 goto Unlock; 1134 } 1135 1136 #ifdef CONFIG_KEXEC_JUMP 1137 if (kexec_image->preserve_context) { 1138 lock_system_sleep(); ^^^^^^^^^^^^^^^^^^^ Here. 1139 pm_prepare_console(); 1140 error = freeze_processes(); 1141 if (error) { 1142 error = -EBUSY; 1143 goto Restore_console; 1144 } 1145 suspend_console(); 1146 error = dpm_suspend_start(PMSG_FREEZE); 1147 if (error) 1148 goto Resume_console; 1149 /* At this point, dpm_suspend_start() has been called, 1150 * but *not* dpm_suspend_end(). We *must* call 1151 * dpm_suspend_end() now. Otherwise, drivers for 1152 * some devices (e.g. interrupt controllers) become 1153 * desynchronized with the actual state of the 1154 * hardware at resume time, and evil weirdness ensues. 1155 */ 1156 error = dpm_suspend_end(PMSG_FREEZE); 1157 if (error) 1158 goto Resume_devices; 1159 error = suspend_disable_secondary_cpus(); 1160 if (error) regards, dan carpenter
WARNING: multiple messages have this Message-ID (diff)
From: Dan Carpenter <dan.carpenter@oracle.com> To: kernelfans@gmail.com Cc: kexec@lists.infradead.org, linux-pm@vger.kernel.org Subject: [bug report] PM / reboot: Eliminate race between reboot and suspend Date: Wed, 18 Nov 2020 21:59:17 +0300 [thread overview] Message-ID: <20201118185917.GA433776@mwanda> (raw) Hello Pingfan Liu, The patch 55f2503c3b69: "PM / reboot: Eliminate race between reboot and suspend" from Jul 31, 2018, leads to the following static checker warning: kernel/power/main.c:27 lock_system_sleep() warn: called with lock held. '&system_transition_mutex' kernel/reboot.c 345 346 mutex_lock(&system_transition_mutex); ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ The patch changed the code to take this lock. 347 switch (cmd) { 348 case LINUX_REBOOT_CMD_RESTART: 349 kernel_restart(NULL); 350 break; 351 352 case LINUX_REBOOT_CMD_CAD_ON: 353 C_A_D = 1; 354 break; 355 356 case LINUX_REBOOT_CMD_CAD_OFF: 357 C_A_D = 0; 358 break; 359 360 case LINUX_REBOOT_CMD_HALT: 361 kernel_halt(); 362 do_exit(0); 363 panic("cannot halt"); 364 365 case LINUX_REBOOT_CMD_POWER_OFF: 366 kernel_power_off(); 367 do_exit(0); 368 break; 369 370 case LINUX_REBOOT_CMD_RESTART2: 371 ret = strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1); 372 if (ret < 0) { 373 ret = -EFAULT; 374 break; 375 } 376 buffer[sizeof(buffer) - 1] = '\0'; 377 378 kernel_restart(buffer); 379 break; 380 381 #ifdef CONFIG_KEXEC_CORE 382 case LINUX_REBOOT_CMD_KEXEC: 383 ret = kernel_kexec(); ^^^^^^^^^^^^^^^^^^^^ Called with lock held. 384 break; 385 #endif But kernel_kexec() also tries to take the &system_transition_mutex so it will dead lock. kernel/kexec_core.c 1125 int kernel_kexec(void) 1126 { 1127 int error = 0; 1128 1129 if (!mutex_trylock(&kexec_mutex)) 1130 return -EBUSY; 1131 if (!kexec_image) { 1132 error = -EINVAL; 1133 goto Unlock; 1134 } 1135 1136 #ifdef CONFIG_KEXEC_JUMP 1137 if (kexec_image->preserve_context) { 1138 lock_system_sleep(); ^^^^^^^^^^^^^^^^^^^ Here. 1139 pm_prepare_console(); 1140 error = freeze_processes(); 1141 if (error) { 1142 error = -EBUSY; 1143 goto Restore_console; 1144 } 1145 suspend_console(); 1146 error = dpm_suspend_start(PMSG_FREEZE); 1147 if (error) 1148 goto Resume_console; 1149 /* At this point, dpm_suspend_start() has been called, 1150 * but *not* dpm_suspend_end(). We *must* call 1151 * dpm_suspend_end() now. Otherwise, drivers for 1152 * some devices (e.g. interrupt controllers) become 1153 * desynchronized with the actual state of the 1154 * hardware at resume time, and evil weirdness ensues. 1155 */ 1156 error = dpm_suspend_end(PMSG_FREEZE); 1157 if (error) 1158 goto Resume_devices; 1159 error = suspend_disable_secondary_cpus(); 1160 if (error) regards, dan carpenter _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
next reply other threads:[~2020-11-18 18:59 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-11-18 18:59 Dan Carpenter [this message] 2020-11-18 18:59 ` [bug report] PM / reboot: Eliminate race between reboot and suspend Dan Carpenter 2021-01-20 9:30 ` Baoquan He 2021-01-20 9:30 ` Baoquan He 2021-01-21 9:10 ` Pingfan Liu 2021-01-21 9:10 ` Pingfan Liu 2021-01-21 14:42 ` Rafael J. Wysocki 2021-01-21 14:42 ` Rafael J. Wysocki 2021-01-22 7:38 ` Baoquan He 2021-01-22 7:38 ` Baoquan He -- strict thread matches above, loose matches on Subject: below -- 2019-11-19 6:18 Dan Carpenter
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