Messages in this thread Patch in this message | | | Date | Thu, 1 Apr 2010 12:51:31 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH 3/12] drivers/char/amiserial.c: Add missing local_irq_restore |
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On Mon, 29 Mar 2010 17:34:11 +0200 (CEST) Julia Lawall <julia@diku.dk> wrote:
> From: Julia Lawall <julia@diku.dk> > > Add local_irq_restore after the labels that can be reached after a > local_irq_save. > > A simplified version of the semantic patch that finds this problem is as > follows: (http://coccinelle.lip6.fr/) > > // <smpl> > @r exists@ > expression E1; > identifier f; > @@ > > f (...) { <+... > * local_irq_save (E1,...); > ... when != E1 > * return ...; > ...+> } > // </smpl> > > Signed-off-by: Julia Lawall <julia@diku.dk> > > --- > drivers/char/amiserial.c | 1 + > 1 files changed, 1 insertions(+), 0 deletions(-) > > diff --git a/drivers/char/amiserial.c b/drivers/char/amiserial.c > index 6c32fbf..2131ecb 100644 > --- a/drivers/char/amiserial.c > +++ b/drivers/char/amiserial.c > @@ -2056,6 +2056,7 @@ fail_free_irq: > free_irq(IRQ_AMIGA_TBE, state); > fail_unregister: > tty_unregister_driver(serial_driver); > + local_irq_restore(flags); > fail_release_mem_region: > release_mem_region(CUSTOM_PHYSADDR+0x30, 4); > fail_put_tty_driver:
We shouldn't be calling tty_unregister_driver() with local interrupts disabled - it does mutex_lock() (at least), which will emit a might_sleep() warning (at least).
I don't expect there was any need to disable irq's across the request_irq() calls (?), hence:
From: Julia Lawall <julia@diku.dk>
rs_init() is failing to restore interrupts on two error paths, and is incorrectly calling tty_unregister_driver() with local interrupts disabled.
Fix these things by disabling interrupts later, after the reauest_irq() calls.
A simplified version of the semantic patch that finds this problem is as follows: (http://coccinelle.lip6.fr/)
// <smpl> @r exists@ expression E1; identifier f; @@
f (...) { <+... * local_irq_save (E1,...); ... when != E1 * return ...; ...+> } // </smpl>
[akpm@linux-foundation.org: reimplement the fix] Signed-off-by: Julia Lawall <julia@diku.dk> Cc: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com> Cc: Greg KH <greg@kroah.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> ---
drivers/char/amiserial.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff -puN drivers/char/amiserial.c~drivers-char-amiserialc-add-missing-local_irq_restore drivers/char/amiserial.c --- a/drivers/char/amiserial.c~drivers-char-amiserialc-add-missing-local_irq_restore +++ a/drivers/char/amiserial.c @@ -2021,8 +2021,6 @@ static int __init rs_init(void) state->baud_base = amiga_colorclock; state->xmit_fifo_size = 1; - local_irq_save(flags); - /* set ISRs, and then disable the rx interrupts */ error = request_irq(IRQ_AMIGA_TBE, ser_tx_int, 0, "serial TX", state); if (error) @@ -2033,6 +2031,8 @@ static int __init rs_init(void) if (error) goto fail_free_irq; + local_irq_save(flags); + /* turn off Rx and Tx interrupts */ custom.intena = IF_RBF | IF_TBE; mb(); _
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