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| author | Heiko Carstens <heiko.carstens@de.ibm.com> | 2008-07-14 09:57:28 +0200 |
|---|---|---|
| committer | Heiko Carstens <heiko.carstens@de.ibm.com> | 2008-07-14 10:02:01 +0200 |
| commit | b9732ca1cb2c18129d2f984b8de02db141b7b830 (patch) | |
| tree | 8614f0d85cace3eaf322ab8b8e429fc1df926927 /drivers | |
| parent | 0c3252d58c54c87ee0f8f40d840e0146a3b1d5fd (diff) | |
| download | lwn-b9732ca1cb2c18129d2f984b8de02db141b7b830.tar.gz lwn-b9732ca1cb2c18129d2f984b8de02db141b7b830.zip | |
[S390] sclp: fix possible deadlock on cpu rescan.
smp_rescan_cpus() calls get_online_cpus() from a multithreaded
workqueue context. This may deadlock. This is the same bug as in
arch/s390/kernel/topology.c. This patch can be reverted as soon as
Oleg's patch gets merged.
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/s390/char/sclp_config.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/s390/char/sclp_config.c b/drivers/s390/char/sclp_config.c index ad05a87bc480..7c9b39cee595 100644 --- a/drivers/s390/char/sclp_config.c +++ b/drivers/s390/char/sclp_config.c @@ -8,6 +8,7 @@ #include <linux/init.h> #include <linux/errno.h> #include <linux/cpu.h> +#include <linux/kthread.h> #include <linux/sysdev.h> #include <linux/workqueue.h> #include <asm/smp.h> @@ -40,9 +41,19 @@ static void sclp_cpu_capability_notify(struct work_struct *work) put_online_cpus(); } -static void __ref sclp_cpu_change_notify(struct work_struct *work) +static int sclp_cpu_kthread(void *data) { smp_rescan_cpus(); + return 0; +} + +static void __ref sclp_cpu_change_notify(struct work_struct *work) +{ + /* Can't call smp_rescan_cpus() from workqueue context since it may + * deadlock in case of cpu hotplug. So we have to create a kernel + * thread in order to call it. + */ + kthread_run(sclp_cpu_kthread, NULL, "cpu_rescan"); } static void sclp_conf_receiver_fn(struct evbuf_header *evbuf) |