Messages in this thread Patch in this message | | | Date | Thu, 11 Sep 2014 09:36:29 +0200 | From | Marc Kleine-Budde <> | Subject | Re: FlexCAN driver triggers kernel BUG in BUSOFF restart |
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On 09/11/2014 06:08 AM, Keith Lugsden wrote: > I was asked by Freescale to post this kernel BUG to you and your email > address appears in the kernel documentation, so please accept my > apologies if you did not wish to see this.
Thanks for the bug report.
> A kernel BUG is triggered during a CAN send operation (kernel version > 3.15.7, stack trace follows below). A simple program, such as the one > included in the kernel's CAN documentation, will cause this problem, as > will the can-utils programs 'cangen' and 'cansend'.
[...]
> Typical stack trace: > > BUG: scheduling while atomic: swapper/0/0/0x00000100 > 1 lock held by swapper/0/0: > #0: (((&priv->restart_timer))){+.-...}, at: [<8002fe60>] > call_timer_fn+0x0/0xe8 > Modules linked in: > CPU: 0 PID: 0 Comm: swapper/0 Tainted: G W 3.15.7 #5 > Backtrace: > [<80011ba4>] (dump_backtrace) from [<80011d40>] (show_stack+0x18/0x1c) > r6:00000000 r5:00000000 r4:00000000 r3:00000000 > [<80011d28>] (show_stack) from [<805de120>] (dump_stack+0x88/0xa4) > [<805de098>] (dump_stack) from [<805db3ec>] (__schedule_bug+0x64/0x7c) > r5:80867268 r4:80867268 > [<805db388>] (__schedule_bug) from [<805e09b0>] (__schedule+0x540/0x5f8) > r4:bf7c7b00 r3:00000002 > [<805e0470>] (__schedule) from [<805e0b5c>] (schedule+0x38/0x88) > r10:8085c000 r9:00000000 r8:00000001 r7:00000000 r6:00004e20 r5:00000000 > r4:00002710 > [<805e0b24>] (schedule) from [<805e03c4>] > (schedule_hrtimeout_range_clock+0xe0/0x158) > [<805e02e4>] (schedule_hrtimeout_range_clock) from [<805e0450>] > (schedule_hrtimeout_range+0x14/0x18) > r10:808644c4 r8:bf335e00 r7:00000000 r6:c09b8000 r5:c09b8000 r4:bf335800 > [<805e043c>] (schedule_hrtimeout_range) from [<8002fb58>] > (usleep_range+0x50/0x58) > [<8002fb08>] (usleep_range) from [<803f2964>] > (flexcan_chip_start+0x7c/0x440) > [<803f28e8>] (flexcan_chip_start) from [<803f3994>] > (flexcan_set_mode+0x28/0x54)
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David Jander already provided a fix for this problem:
8badd65 can: flexcan: avoid calling usleep_range from interrupt context
It will hit mainline soon and then be backported to the stable trees.
Marc
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From 8badd65e48c90d66587359d5329c2813088c0f50 Mon Sep 17 00:00:00 2001 From: David Jander <david@protonic.nl> Date: Wed, 27 Aug 2014 12:02:16 +0200 Subject: [PATCH] can: flexcan: avoid calling usleep_range from interrupt context
Apparently can_restart() runs from a (timer-) interrupt and can call flexcan_chip_[en|dis]able(), so avoid using usleep_range()
Signed-off-by: David Jander <david@protonic.nl> Cc: linux-stable <stable@vger.kernel.org> Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de> --- drivers/net/can/flexcan.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index 944aa5d..630c7bf 100644 --- a/drivers/net/can/flexcan.c +++ b/drivers/net/can/flexcan.c @@ -298,7 +298,7 @@ static int flexcan_chip_enable(struct flexcan_priv *priv) flexcan_write(reg, ®s->mcr); while (timeout-- && (flexcan_read(®s->mcr) & FLEXCAN_MCR_LPM_ACK)) - usleep_range(10, 20); + udelay(10); if (flexcan_read(®s->mcr) & FLEXCAN_MCR_LPM_ACK) return -ETIMEDOUT; @@ -317,7 +317,7 @@ static int flexcan_chip_disable(struct flexcan_priv *priv) flexcan_write(reg, ®s->mcr); while (timeout-- && !(flexcan_read(®s->mcr) & FLEXCAN_MCR_LPM_ACK)) - usleep_range(10, 20); + udelay(10); if (!(flexcan_read(®s->mcr) & FLEXCAN_MCR_LPM_ACK)) return -ETIMEDOUT; @@ -336,7 +336,7 @@ static int flexcan_chip_freeze(struct flexcan_priv *priv) flexcan_write(reg, ®s->mcr); while (timeout-- && !(flexcan_read(®s->mcr) & FLEXCAN_MCR_FRZ_ACK)) - usleep_range(100, 200); + udelay(100); if (!(flexcan_read(®s->mcr) & FLEXCAN_MCR_FRZ_ACK)) return -ETIMEDOUT; @@ -355,7 +355,7 @@ static int flexcan_chip_unfreeze(struct flexcan_priv *priv) flexcan_write(reg, ®s->mcr); while (timeout-- && (flexcan_read(®s->mcr) & FLEXCAN_MCR_FRZ_ACK)) - usleep_range(10, 20); + udelay(10); if (flexcan_read(®s->mcr) & FLEXCAN_MCR_FRZ_ACK) return -ETIMEDOUT; @@ -370,7 +370,7 @@ static int flexcan_chip_softreset(struct flexcan_priv *priv) flexcan_write(FLEXCAN_MCR_SOFTRST, ®s->mcr); while (timeout-- && (flexcan_read(®s->mcr) & FLEXCAN_MCR_SOFTRST)) - usleep_range(10, 20); + udelay(10); if (flexcan_read(®s->mcr) & FLEXCAN_MCR_SOFTRST) return -ETIMEDOUT; -- 2.1.0 -- Pengutronix e.K. | Marc Kleine-Budde | Industrial Linux Solutions | Phone: +49-231-2826-924 | Vertretung West/Dortmund | Fax: +49-5121-206917-5555 | Amtsgericht Hildesheim, HRA 2686 | http://www.pengutronix.de | [unhandled content-type:application/pgp-signature] | |