diff options
| author | Sukadev Bhattiprolu <sukadev@linux.vnet.ibm.com> | 2017-11-28 13:39:43 -0600 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-02-22 15:39:55 +0100 |
| commit | 676fafcce904fcd25d0f5059972002990c45d8a8 (patch) | |
| tree | 6917090ee71fc7f291cfefc5c6db314ed5711b44 /arch/powerpc | |
| parent | 8119b8ed2062dfd346054882743cb040eaa9e31e (diff) | |
powerpc/kernel: Block interrupts when updating TIDR
commit 384dfd627f1ee67d028e6f14c6e9bf5a1e2a7a24 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/powerpc')
| -rw-r--r-- | arch/powerpc/kernel/process.c | 15 |
1 files changed, 9 insertions, 6 deletions
diff --git a/arch/powerpc/kernel/process.c b/arch/powerpc/kernel/process.c index 72be0c32e902..2010e4c827b7 100644 --- a/arch/powerpc/kernel/process.c +++ b/arch/powerpc/kernel/process.c @@ -1509,14 +1509,15 @@ 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; @@ -1524,9 +1525,9 @@ 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; } @@ -1535,9 +1536,11 @@ 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); } /* |