Thread (11 messages) 11 messages, 3 authors, 2017-10-26

Re: alpha boot hang - 4.14-rc* regression

From: Lorenzo Pieralisi <hidden>
Date: 2017-10-25 13:37:27
Also in: linux-pci, lkml
Subsystem: alpha port, the rest · Maintainers: Richard Henderson, Matt Turner, Magnus Lindholm, Linus Torvalds

On Wed, Oct 25, 2017 at 03:21:21PM +0300, Meelis Roos wrote:
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(Added linux-pci to CC)
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I run Gentoo Linux on my alphas, with latest git kernels for test. 
4.13.0 worked well on 3 alphas but 4.13.0-09217-g5969d1bb3082 hangs on 
boot on all 3 of them. Tried bisecting on PC164, got into unrelated 
stuff, so probably it does not trigger always. Retried bisecting on 
DS10L. On the first try I got that the same keel where I first saw bad 
was the culprit, another bisect led me to 
0e4c2eeb758a91e68b9eaf7a4bee9bd5ed97ff2b which looks more related.

This is how the crash looks on console:

 * Starting udev ...
starting version 225
 [ ok ]
 * Generating a rule to create a /dev/root symlink ...
 [ ok ]
 * Populating /dev with existing devices through uevents ...
 [ ok ]

halted CPU 0

halt code = 5
HALT instruction executed
PC = fffffc00009bf914
boot failure
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What else can I do to debug this?
Booting with debug ignore_loglevel I get also this:
[...]
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So maybe it is related pcspkr loading, or the just loaded libata or 
floppy...
removing libata modules and rebooting fixes it - so it seems to be 
loading of libata.
Can you please cherry-pick:

commit b1f9e5e355e9 ("ide: fix IRQ assignment for PCI bus order probing")

from mainline and let us know if that solves the issue ?
No, still breaks the same way (b1f9e5e355e9 patched on top of 
0e4c2eeb758a).

4.14.0-rc5-00095-g1c9fec470b81 was also still broken the same way (tried 
on Sunday).
I am not sure I patched the right sys file but if I did, does the patch
below help ?

I think that at sata driver binding time the kernel finds a freed
pointer in the host bridge map_irq() hook and that's where things
go wrong.

Please let me know if that's the right sys file, it is a mechanical
change and making it for other sys file should be reasonably simple.

Lorenzo

-- >8 --
diff --git a/arch/alpha/kernel/sys_dp264.c b/arch/alpha/kernel/sys_dp264.c
index 6c35159..88c72fe 100644
--- a/arch/alpha/kernel/sys_dp264.c
+++ b/arch/alpha/kernel/sys_dp264.c
@@ -356,7 +356,7 @@
  *  10	 64 bit PCI option slot 3 (not bus 0)
  */
 
-static int __init
+static int
 isa_irq_fixup(const struct pci_dev *dev, int irq)
 {
 	u8 irq8;
@@ -372,10 +372,10 @@
 	return irq8 & 0xf;
 }
 
-static int __init
+static int
 dp264_map_irq(const struct pci_dev *dev, u8 slot, u8 pin)
 {
-	static char irq_tab[6][5] __initdata = {
+	static char irq_tab[6][5] = {
 		/*INT    INTA   INTB   INTC   INTD */
 		{    -1,    -1,    -1,    -1,    -1}, /* IdSel 5 ISA Bridge */
 		{ 16+ 3, 16+ 3, 16+ 2, 16+ 2, 16+ 2}, /* IdSel 6 SCSI builtin*/
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