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Message-ID: <20130205181310.GB1124@x61s.8.8.8.8> Date: Tue, 5 Feb 2013 19:13:11 +0100 From: Alexander Aring <alex.aring@...il.com> To: Eric Dumazet <eric.dumazet@...il.com> Cc: alex.bluesman.smirnov@...il.com, dbaryshkov@...il.com, linux-zigbee-devel@...ts.sourceforge.net, davem@...emloft.net, netdev@...r.kernel.org Subject: Re: [PATCH] wpan: use GFP_ATOMIC instead of GFP_KERNEL Hi, On Tue, Feb 05, 2013 at 07:00:57PM +0100, Alexander Aring wrote: > Hi, > > thanks for your reply. > > On Tue, Feb 05, 2013 at 08:09:57AM -0800, Eric Dumazet wrote: > > On Tue, 2013-02-05 at 16:34 +0100, Alexander Aring wrote: > > > I got this message at runtime: > > > > > > [ 48.847347] BUG: scheduling while atomic: swapper/0/0/0x40000100 > > > [ 48.853870] Modules linked in: autofs4 > > > [ 48.857891] [<c0013db8>] (unwind_backtrace+0x0/0x11c) from [<c04cfb84>] (__schedule_bug+0x48/0x5c) > > > [ 48.867342] [<c04cfb84>] (__schedule_bug+0x48/0x5c) from [<c04e0f4c>] (__schedule+0x68/0x5bc) > > > [ 48.876357] [<c04e0f4c>] (__schedule+0x68/0x5bc) from [<c0063f0c>] (__cond_resched+0x24/0x34) > > > [ 48.885368] [<c0063f0c>] (__cond_resched+0x24/0x34) from [<c04e152c>] (_cond_resched+0x34/0x44) > > > [ 48.894559] [<c04e152c>] (_cond_resched+0x34/0x44) from [<c00e9b28>] (kmem_cache_alloc_trace+0x2c/0x158) > > > [ 48.904578] [<c00e9b28>] (kmem_cache_alloc_trace+0x2c/0x158) from [<c04baa3c>] (mac802154_header_create+0x44/0x2) > > > [ 48.915594] [<c04baa3c>] (mac802154_header_create+0x44/0x24c) from [<c04b8e50>] (lowpan_header_create.part.3+0x7) > > > [ 48.927157] [<c04b8e50>] (lowpan_header_create.part.3+0x734/0x79c) from [<c03ebc04>] (neigh_connected_output+0x9) > > > [ 48.938542] [<c03ebc04>] (neigh_connected_output+0x98/0xd0) from [<c0467d5c>] (ip6_finish_output2+0x374/0x45c) > > > [ 48.949102] [<c0467d5c>] (ip6_finish_output2+0x374/0x45c) from [<c0479bcc>] (ndisc_send_skb+0x174/0x22c) > > > [ 48.959101] [<c0479bcc>] (ndisc_send_skb+0x174/0x22c) from [<c047b138>] (ndisc_send_rs+0x3c/0x44) > > > [ 48.968473] [<c047b138>] (ndisc_send_rs+0x3c/0x44) from [<c046e3f0>] (addrconf_rs_timer+0xbc/0x16c) > > > [ 48.978032] [<c046e3f0>] (addrconf_rs_timer+0xbc/0x16c) from [<c00451fc>] (call_timer_fn+0x74/0x134) > > > [ 48.987675] [<c00451fc>] (call_timer_fn+0x74/0x134) from [<c0046984>] (run_timer_softirq+0x258/0x2d4) > > > [ 48.997417] [<c0046984>] (run_timer_softirq+0x258/0x2d4) from [<c003fb84>] (__do_softirq+0x118/0x248) > > > [ 49.007156] [<c003fb84>] (__do_softirq+0x118/0x248) from [<c003ff64>] (irq_exit+0x44/0x84) > > > [ 49.015890] [<c003ff64>] (irq_exit+0x44/0x84) from [<c000e780>] (handle_IRQ+0x7c/0xb8) > > > [ 49.024249] [<c000e780>] (handle_IRQ+0x7c/0xb8) from [<c000857c>] (omap3_intc_handle_irq+0x54/0x68) > > > [ 49.033801] [<c000857c>] (omap3_intc_handle_irq+0x54/0x68) from [<c04e2900>] (__irq_svc+0x40/0x50) > > > [ 49.043239] Exception stack(0xc074bf68 to 0xc074bfb0) > > > [ 49.048576] bf60: ffffffed 00000000 002f8000 00000000 c074a000 c07b6608 > > > [ 49.057199] bf80: c04ec10c c0757618 80004059 413fc082 00000000 00000000 00000000 c074bfb0 > > > [ 49.065821] bfa0: c000e904 c000e908 60000013 ffffffff > > > [ 49.071162] [<c04e2900>] (__irq_svc+0x40/0x50) from [<c000e908>] (default_idle+0x24/0x2c) > > > [ 49.079789] [<c000e908>] (default_idle+0x24/0x2c) from [<c000ea7c>] (cpu_idle+0x9c/0xf0) > > > [ 49.088328] [<c000ea7c>] (cpu_idle+0x9c/0xf0) from [<c06ff7dc>] (start_kernel+0x258/0x2a4) > > > > > > It seems that mac802154_header_create is calling from a irq context. > > > So kzalloc need GFP_ATOMIC flag. > > > > > > This patch will fix it. > > > > > > Signed-off-by: Alexander Aring <alex.aring@...il.com> > > > --- > > > net/mac802154/wpan.c | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/net/mac802154/wpan.c b/net/mac802154/wpan.c > > > index 98c867b..0d9e110 100644 > > > --- a/net/mac802154/wpan.c > > > +++ b/net/mac802154/wpan.c > > > @@ -143,7 +143,7 @@ static int mac802154_header_create(struct sk_buff *skb, > > > if (!daddr) > > > return -EINVAL; > > > > > > - head = kzalloc(MAC802154_FRAME_HARD_HEADER_LEN, GFP_KERNEL); > > > + head = kzalloc(MAC802154_FRAME_HARD_HEADER_LEN, GFP_ATOMIC); > > > if (head == NULL) > > > return -ENOMEM; > > > > > > > Please remove this allocation, its absolutely not needed. > > I don't know how I can do that. head is a temp buffer. > At the end of this function stands: > > memcpy(skb_push(skb, pos), head, pos) > > and 'pos' is determined at runtime. skb_push will add data to the > start of buffer, so head buffer will be at the start of skb. I don't > know where I should manipulate the skb buffer at beginning of this function. > > Regards > Alex Ahh, you mean to put it on the stack. :-) Sorry about that. > > > > > 40 bytes on the stack are fine. > > > > Thanks > > > > -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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