diff options
author | Rabin Vincent <rabin@rab.in> | 2015-02-20 21:35:16 +0300 |
---|---|---|
committer | Jesper Nilsson <jespern@axis.com> | 2015-09-05 01:56:50 +0300 |
commit | 7f0144e7779a8c62e3177301d4b2179432ce5460 (patch) | |
tree | 2b35d7d0b91f9f9af471c4df50a481a8ce1858fc /arch/cris/include/asm/mmu_context.h | |
parent | 94c5c115c1f7d347d5ec7f32a090f8643dd42525 (diff) | |
download | linux-7f0144e7779a8c62e3177301d4b2179432ce5460.tar.xz |
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/cris/include/asm/mmu_context.h')
-rw-r--r-- | arch/cris/include/asm/mmu_context.h | 9 |
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 |