summaryrefslogtreecommitdiff
path: root/arch
diff options
context:
space:
mode:
authorRabin Vincent <rabin@rab.in>2015-02-20 19:35:16 +0100
committerJesper Nilsson <jespern@axis.com>2015-09-05 00:56:50 +0200
commit7f0144e7779a8c62e3177301d4b2179432ce5460 (patch)
tree2b35d7d0b91f9f9af471c4df50a481a8ce1858fc /arch
parent94c5c115c1f7d347d5ec7f32a090f8643dd42525 (diff)
downloadlinux-7f0144e7779a8c62e3177301d4b2179432ce5460.tar.gz
CRIS: fix switch_mm() lockdep splat
With lockdep support implemented on CRISv32, we get the following splat. switch_mm() can be called both from the scheduler() (with interrupts disabled) and from flush_old_exec (via activate_mm()), with interrupts enabled. Fix it by disabling interrupts in activate_mm(), similar to powerpc and hexagon. t====================================================== [ INFO: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected ] 3.19.0-08802-g20bc9f1-dirty #323 Not tainted ------------------------------------------------------ init/1 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire: (mmu_context_lock){+.+...}, at: [<c0009290>] switch_mm+0x22/0xc6 and this task is already holding: (&rq->lock){-.-.-.}, at: [<c01a0756>] __schedule+0x5e/0x648 which would create a new lock dependency: (&rq->lock){-.-.-.} -> (mmu_context_lock){+.+...} but this new dependency connects a HARDIRQ-irq-safe lock: (&rq->lock){-.-.-.} ... which became HARDIRQ-irq-safe at: [<c002b03c>] scheduler_tick+0x28/0x5e [<c0007c6c>] timer_interrupt+0x4e/0x6a [<c0043ac4>] handle_irq_event_percpu+0x54/0x13c [<c004343c>] generic_handle_irq+0x2a/0x36 to a HARDIRQ-irq-unsafe lock: (mmu_context_lock){+.+...} ... which became HARDIRQ-irq-unsafe at: ... [<c0039e60>] __lock_acquire+0x8f8/0x1d9c [<c0009290>] switch_mm+0x22/0xc6 [<c009c260>] flush_old_exec+0x500/0x5d4 [<c00da4c6>] load_elf_phdrs+0x7a/0x84 [<c00dbdb0>] load_elf_binary+0x21c/0x13b4 [<c009cdb6>] do_execve+0x22/0x2c [<c001dcf2>] ____call_usermodehelper+0x0/0x154 [<c000581e>] ret_from_kernel_thread+0xe/0x14 other info that might help us debug this: Possible interrupt unsafe locking scenario: CPU0 CPU1 ---- ---- lock(mmu_context_lock); local_irq_disable(); lock(&rq->lock); lock(mmu_context_lock); <Interrupt> lock(&rq->lock); *** DEADLOCK *** 1 lock held by init/1: #0: (&rq->lock){-.-.-.}, at: [<c01a0756>] __schedule+0x5e/0x648 Call Trace: [<c019fe9e>] printk+0x0/0x4e [<c00368f8>] print_shortest_lock_dependencies+0x0/0x15c [<c0048628>] print_stack_trace+0x0/0x88 [<c0038912>] __lock_is_held+0x3e/0x5e [<c003b894>] lock_acquire+0x8a/0xcc [<c01a50c4>] _raw_spin_lock+0x44/0x7a [<c0009290>] switch_mm+0x22/0xc6 [<c01a06f8>] __schedule+0x0/0x648 [<c01a0d76>] schedule+0x36/0x7c [<c0037d04>] trace_hardirqs_on+0x0/0x1e [<c0004e18>] do_work_pending+0x30/0xd4 [<c000591a>] _work_pending+0xe/0x12 Signed-off-by: Rabin Vincent <rabin@rab.in> Signed-off-by: Jesper Nilsson <jesper.nilsson@axis.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/cris/include/asm/mmu_context.h9
1 files changed, 8 insertions, 1 deletions
diff --git a/arch/cris/include/asm/mmu_context.h b/arch/cris/include/asm/mmu_context.h
index 1d45fd6365b7..349acfd25d2f 100644
--- a/arch/cris/include/asm/mmu_context.h
+++ b/arch/cris/include/asm/mmu_context.h
@@ -11,7 +11,14 @@ extern void switch_mm(struct mm_struct *prev, struct mm_struct *next,
#define deactivate_mm(tsk,mm) do { } while (0)
-#define activate_mm(prev,next) switch_mm((prev),(next),NULL)
+static inline void activate_mm(struct mm_struct *prev, struct mm_struct *next)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ switch_mm(prev, next, NULL);
+ local_irq_restore(flags);
+}
/* current active pgd - this is similar to other processors pgd
* registers like cr3 on the i386