From: Tomi Valkeinen <email@example.com> To: Tony Lindgren <firstname.lastname@example.org> Cc: email@example.com, Nishanth Menon <firstname.lastname@example.org>, "Bajjuri, Praneeth" <email@example.com>, firstname.lastname@example.org Subject: Re: Random stack corruption on v5.13 with dra76 Date: Fri, 21 May 2021 13:30:58 +0300 [thread overview] Message-ID: <email@example.com> (raw) In-Reply-To: <YKd56/KAnIUIm7K5@atomide.com> On 21/05/2021 12:14, Tony Lindgren wrote: > * Tomi Valkeinen <firstname.lastname@example.org> [210521 08:45]: >> On 21/05/2021 10:39, Tony Lindgren wrote: >>> * Tomi Valkeinen <email@example.com> [210521 07:05]: >>>> On 21/05/2021 08:36, Tony Lindgren wrote: >>>>> * Tomi Valkeinen <firstname.lastname@example.org> [210520 08:27]: >>>>>> Hi, >>>>>> >>>>>> I've noticed that the v5.13 rcs crash randomly (but quite often) on dra76 evm >>>>>> (I haven't tested other boards). Anyone else seen this problem? >>>>> >>>>> I have not seen this so far and beagle-x15 is behaving for me. >>>>> >>>>> Does it always happen on boot? >>>> >>>> No, but quite often. I can't really say how often, as it's annoyingly random. >>>> I tried to bisect, but that proved to be difficult as sometimes I get multiple (5+) >>>> successful boots before the crash. >>>> >>>> I tested with x15, same issue (below). So... Something in my kernel config? Or compiler? >>>> Looks like the crash happens always very soon after (or during) probing palmas. >>> >>> After about 10 reboots with your .config I'm seeing it now too on >>> beagle-x15. So far no luck reproducing it with omap2plus_defconfig. >> >> I think I have an easy way to see if a kernel is good or bad, by printing >> stack_not_used(current) in the first call to omap_i2c_xfer_irq(). There's a >> huge drop between v5.12 and v5.13-rc1. >> >> And interestingly, sometimes a simple printk seems to use hundreds of bytes >> of stack (i.e. compare stack usage before and after the print). But not >> always. So maybe the issue is somehow related to printk. >> >> I'm bisecting. > > OK sounds good to me. Well, I found the bad commit but unfortunately it doesn't exactly point where the issue is. f483a3e123410bd1c78af295bf65feffb6769a98 is the first bad commit commit f483a3e123410bd1c78af295bf65feffb6769a98 Author: Tony Lindgren <email@example.com> Date: Wed Mar 10 14:03:48 2021 +0200 ARM: dts: Configure simple-pm-bus for dra7 l4_per1 We can now probe interconnects with device tree only configuration using simple-pm-bus and genpd. Tested-by: Kishon Vijay Abraham I <firstname.lastname@example.org> Signed-off-by: Tony Lindgren <email@example.com> arch/arm/boot/dts/dra7-l4.dtsi | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) The difference is clear, though. With 9a75368b6426739e8b798592f084cb682d760568, which is the last good commit, when I print the stack usage with stack_not_used() in three different places in omap_i2c_xfer_irq(), I get always prints roughly like: STACK FREE omap_i2c_xfer_irq: 2972, 2972, 2972 And these repeat exactly the same for each call to omap_i2c_xfer_irq (at least during palmas probe). With the bad commit the situation is different. The first call to omap_i2c_xfer_irq prints: STACK FREE omap_i2c_xfer_irq: 2024, 2024, 2024 so we're already using 1k more. But then, instead of the stack usage staying the same, consecutive calls show increased stack usage. It doesn't increase for each xfer call, but after about 10 calls, I'm getting ~1800, ten calls more I see ~800, and going down to ~500. However, with this bad commit, I don't see the empty stack going below ~500, so I don't get crashes. But going to a more recent commit, like 01d7136894410a71932096e0fb9f1d301b6ccf07, the situation is much worse. The first print shows: STACK FREE omap_i2c_xfer_irq: 1164, 1164, 1164 and it quickly goes to stack overflow. Tomi _______________________________________________ linux-arm-kernel mailing list firstname.lastname@example.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2021-05-21 10:32 UTC|newest] Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top [not found] <email@example.com> 2021-05-21 5:36 ` Tony Lindgren 2021-05-21 7:04 ` Tomi Valkeinen 2021-05-21 7:39 ` Tony Lindgren 2021-05-21 8:45 ` Tomi Valkeinen 2021-05-21 9:14 ` Tony Lindgren 2021-05-21 10:30 ` Tomi Valkeinen [this message] 2021-05-21 12:57 ` Tomi Valkeinen 2021-05-21 13:06 ` Tony Lindgren
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