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authorLinus Torvalds <torvalds@linux-foundation.org>2014-06-06 16:35:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-06 16:35:10 -0700
commit57d326169e878a1a37b2bccd1cf81f6809ee67b9 (patch)
tree86ed74ae4dc2beaebce1c67b8459f1873b777d3a /drivers/tty/sysrq.c
parent7b215de3d0abbc4f6daf2efd19e8809af0564490 (diff)
parent0244756edc4b98c129e92c7061d9f383708cf786 (diff)
downloadlinux-57d326169e878a1a37b2bccd1cf81f6809ee67b9.tar.bz2
Merge branch 'akpm' (patches from Andrew Morton) into next
Merge more updates from Andrew Morton: - Most of the rest of MM. This includes "mark remap_file_pages syscall as deprecated" but the actual "replace remap_file_pages syscall with emulation" is held back. I guess we'll need to work out when to pull the trigger on that one. - various minor cleanups to obscure filesystems - the drivers/rtc queue - hfsplus updates - ufs, hpfs, fatfs, affs, reiserfs - Documentation/ - signals - procfs - cpu hotplug - lib/idr.c - rapidio - sysctl - ipc updates * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (171 commits) ufs: sb mutex merge + mutex_destroy powerpc: update comments for generic idle conversion cris: update comments for generic idle conversion idle: remove cpu_idle() forward declarations nbd: zero from and len fields in NBD_CMD_DISCONNECT. mm: convert some level-less printks to pr_* MAINTAINERS: adi-buildroot-devel is moderated MAINTAINERS: add linux-api for review of API/ABI changes mm/kmemleak-test.c: use pr_fmt for logging fs/dlm/debug_fs.c: replace seq_printf by seq_puts fs/dlm/lockspace.c: convert simple_str to kstr fs/dlm/config.c: convert simple_str to kstr mm: mark remap_file_pages() syscall as deprecated mm: memcontrol: remove unnecessary memcg argument from soft limit functions mm: memcontrol: clean up memcg zoneinfo lookup mm/memblock.c: call kmemleak directly from memblock_(alloc|free) mm/mempool.c: update the kmemleak stack trace for mempool allocations lib/radix-tree.c: update the kmemleak stack trace for radix tree allocations mm: introduce kmemleak_update_trace() mm/kmemleak.c: use %u to print ->checksum ...
Diffstat (limited to 'drivers/tty/sysrq.c')
-rw-r--r--drivers/tty/sysrq.c21
1 files changed, 15 insertions, 6 deletions
diff --git a/drivers/tty/sysrq.c b/drivers/tty/sysrq.c
index b767a64e49d9..454b65898e2c 100644
--- a/drivers/tty/sysrq.c
+++ b/drivers/tty/sysrq.c
@@ -46,6 +46,7 @@
#include <linux/jiffies.h>
#include <linux/syscalls.h>
#include <linux/of.h>
+#include <linux/rcupdate.h>
#include <asm/ptrace.h>
#include <asm/irq_regs.h>
@@ -510,9 +511,9 @@ void __handle_sysrq(int key, bool check_mask)
struct sysrq_key_op *op_p;
int orig_log_level;
int i;
- unsigned long flags;
- spin_lock_irqsave(&sysrq_key_table_lock, flags);
+ rcu_sysrq_start();
+ rcu_read_lock();
/*
* Raise the apparent loglevel to maximum so that the sysrq header
* is shown to provide the user with positive feedback. We do not
@@ -554,7 +555,8 @@ void __handle_sysrq(int key, bool check_mask)
printk("\n");
console_loglevel = orig_log_level;
}
- spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
+ rcu_read_unlock();
+ rcu_sysrq_end();
}
void handle_sysrq(int key)
@@ -1043,16 +1045,23 @@ static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
struct sysrq_key_op *remove_op_p)
{
int retval;
- unsigned long flags;
- spin_lock_irqsave(&sysrq_key_table_lock, flags);
+ spin_lock(&sysrq_key_table_lock);
if (__sysrq_get_key_op(key) == remove_op_p) {
__sysrq_put_key_op(key, insert_op_p);
retval = 0;
} else {
retval = -1;
}
- spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
+ spin_unlock(&sysrq_key_table_lock);
+
+ /*
+ * A concurrent __handle_sysrq either got the old op or the new op.
+ * Wait for it to go away before returning, so the code for an old
+ * op is not freed (eg. on module unload) while it is in use.
+ */
+ synchronize_rcu();
+
return retval;
}