[1/2] powerpc/powernv: Fix opal_event_shutdown() called with interrupts disabled

Message ID 20180514155947.22753-2-npiggin@gmail.com
State Accepted
Commit c0beffc4f4c658fde86d52c837e784326e9cc875
Headers show
Series
  • sleeping functions in invalid context on panic fixes
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Commit Message

Nicholas Piggin May 14, 2018, 3:59 p.m.
A kernel crash in process context that calls emergency_restart from
panic will end up calling opal_event_shutdown with interrupts disabled
but not in interrupt. This causes a sleeping function to be called
which gives the following warning with sysrq+c:

    Rebooting in 10 seconds..
    BUG: sleeping function called from invalid context at kernel/locking/mutex.c:238
    in_atomic(): 0, irqs_disabled(): 1, pid: 7669, name: bash
    CPU: 20 PID: 7669 Comm: bash Tainted: G      D W         4.17.0-rc5+ #3
    Call Trace:
    dump_stack+0xb0/0xf4 (unreliable)
    ___might_sleep+0x174/0x1a0
    mutex_lock+0x38/0xb0
    __free_irq+0x68/0x460
    free_irq+0x70/0xc0
    opal_event_shutdown+0xb4/0xf0
    opal_shutdown+0x24/0xa0
    pnv_shutdown+0x28/0x40
    machine_shutdown+0x44/0x60
    machine_restart+0x28/0x80
    emergency_restart+0x30/0x50
    panic+0x2a0/0x328
    oops_end+0x1ec/0x1f0
    bad_page_fault+0xe8/0x154
    handle_page_fault+0x34/0x38
    --- interrupt: 300 at sysrq_handle_crash+0x44/0x60
    LR = __handle_sysrq+0xfc/0x260
    flag_spec.62335+0x12b844/0x1e8db4 (unreliable)
    __handle_sysrq+0xfc/0x260
    write_sysrq_trigger+0xa8/0xb0
    proc_reg_write+0xac/0x110
    __vfs_write+0x6c/0x240
    vfs_write+0xd0/0x240
    ksys_write+0x6c/0x110

Fixes: 9f0fd0499d30 ("powerpc/powernv: Add a virtual irqchip for opal events")
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/platforms/powernv/opal-irqchip.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Michael Ellerman May 21, 2018, 10:01 a.m. | #1
On Mon, 2018-05-14 at 15:59:46 UTC, Nicholas Piggin wrote:
> A kernel crash in process context that calls emergency_restart from
> panic will end up calling opal_event_shutdown with interrupts disabled
> but not in interrupt. This causes a sleeping function to be called
> which gives the following warning with sysrq+c:
> 
>     Rebooting in 10 seconds..
>     BUG: sleeping function called from invalid context at kernel/locking/mutex.c:238
>     in_atomic(): 0, irqs_disabled(): 1, pid: 7669, name: bash
>     CPU: 20 PID: 7669 Comm: bash Tainted: G      D W         4.17.0-rc5+ #3
>     Call Trace:
>     dump_stack+0xb0/0xf4 (unreliable)
>     ___might_sleep+0x174/0x1a0
>     mutex_lock+0x38/0xb0
>     __free_irq+0x68/0x460
>     free_irq+0x70/0xc0
>     opal_event_shutdown+0xb4/0xf0
>     opal_shutdown+0x24/0xa0
>     pnv_shutdown+0x28/0x40
>     machine_shutdown+0x44/0x60
>     machine_restart+0x28/0x80
>     emergency_restart+0x30/0x50
>     panic+0x2a0/0x328
>     oops_end+0x1ec/0x1f0
>     bad_page_fault+0xe8/0x154
>     handle_page_fault+0x34/0x38
>     --- interrupt: 300 at sysrq_handle_crash+0x44/0x60
>     LR = __handle_sysrq+0xfc/0x260
>     flag_spec.62335+0x12b844/0x1e8db4 (unreliable)
>     __handle_sysrq+0xfc/0x260
>     write_sysrq_trigger+0xa8/0xb0
>     proc_reg_write+0xac/0x110
>     __vfs_write+0x6c/0x240
>     vfs_write+0xd0/0x240
>     ksys_write+0x6c/0x110
> 
> Fixes: 9f0fd0499d30 ("powerpc/powernv: Add a virtual irqchip for opal events")
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/c0beffc4f4c658fde86d52c837e784

cheers

Patch

diff --git a/arch/powerpc/platforms/powernv/opal-irqchip.c b/arch/powerpc/platforms/powernv/opal-irqchip.c
index 9d1b8c0aaf93..05ffe05f0fdc 100644
--- a/arch/powerpc/platforms/powernv/opal-irqchip.c
+++ b/arch/powerpc/platforms/powernv/opal-irqchip.c
@@ -177,7 +177,7 @@  void opal_event_shutdown(void)
 		if (!opal_irqs[i])
 			continue;
 
-		if (in_interrupt())
+		if (in_interrupt() || irqs_disabled())
 			disable_irq_nosync(opal_irqs[i]);
 		else
 			free_irq(opal_irqs[i], NULL);