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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> |
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| arch-v32 | ||
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