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authorSukadev Bhattiprolu <sukadev@linux.vnet.ibm.com>2017-11-28 22:39:43 +0300
committerMichael Ellerman <mpe@ellerman.id.au>2018-01-27 12:54:57 +0300
commit384dfd627f1ee67d028e6f14c6e9bf5a1e2a7a24 (patch)
tree2d75e570ecca643bef1eaca852215898d134b3a5 /arch/powerpc/kernel
parent902bdc57451c2c64aa139bbe24067f70a186db0a (diff)
downloadlinux-384dfd627f1ee67d028e6f14c6e9bf5a1e2a7a24.tar.xz
powerpc/kernel: Block interrupts when updating TIDR
clear_thread_tidr() is called in interrupt context as a part of delayed put of the task structure (i.e as a part of timer interrupt). To prevent a deadlock, block interrupts when holding vas_thread_id_lock to set/ clear TIDR for a task. Fixes: ec233ede4c86 ("powerpc: Add support for setting SPRN_TIDR") Cc: stable@vger.kernel.org # v4.15+ Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel')
-rw-r--r--arch/powerpc/kernel/process.c15
1 files changed, 9 insertions, 6 deletions
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c
index 2fd01c9045ba..69af583dce98 100644
--- a/arch/powerpc/kernel/process.c
+++ b/arch/powerpc/kernel/process.c
@@ -1515,14 +1515,15 @@ static int assign_thread_tidr(void)
{
int index;
int err;
+ unsigned long flags;
again:
if (!ida_pre_get(&vas_thread_ida, GFP_KERNEL))
return -ENOMEM;
- spin_lock(&vas_thread_id_lock);
+ spin_lock_irqsave(&vas_thread_id_lock, flags);
err = ida_get_new_above(&vas_thread_ida, 1, &index);
- spin_unlock(&vas_thread_id_lock);
+ spin_unlock_irqrestore(&vas_thread_id_lock, flags);
if (err == -EAGAIN)
goto again;
@@ -1530,9 +1531,9 @@ again:
return err;
if (index > MAX_THREAD_CONTEXT) {
- spin_lock(&vas_thread_id_lock);
+ spin_lock_irqsave(&vas_thread_id_lock, flags);
ida_remove(&vas_thread_ida, index);
- spin_unlock(&vas_thread_id_lock);
+ spin_unlock_irqrestore(&vas_thread_id_lock, flags);
return -ENOMEM;
}
@@ -1541,9 +1542,11 @@ again:
static void free_thread_tidr(int id)
{
- spin_lock(&vas_thread_id_lock);
+ unsigned long flags;
+
+ spin_lock_irqsave(&vas_thread_id_lock, flags);
ida_remove(&vas_thread_ida, id);
- spin_unlock(&vas_thread_id_lock);
+ spin_unlock_irqrestore(&vas_thread_id_lock, flags);
}
/*