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amba-pl011: fix panic introduced by "clear pending interrupts"

PATCH In review Alessandro Rubini 3 participants 3 messages Mar 26, 2012 – Mar 27, 2012

Subsystems (2)
TTY layer and serial drivers Arm primecell UART PL010 and PL011 drivers
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Alessandro Rubini

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#0 lore raw

PATCH 1/1 amba-pl011: fix panic introduced by "clear pending interrupts"

patch 9b96fba, currently in linux-next, clears interrupts using uap->port.membase that has not been assigned. My x86 system, that uses a pci-to-amba bridge, panics with a message like:

   BUG: unable to handle kernel NULL pointer dereference at 00000038
   IP: [<c12c85ed>] pl011_probe+0x119/0x303
Signed-off-by Alessandro Rubini <[email protected]>
Acked-by Giancarlo Asnaghi <[email protected]>
---
 drivers/tty/serial/amba-pl011.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
drivers/tty/serial/amba-pl011.c +2 -2
index 2b4e981..38c992d 100644
@@ -1947,8 +1947,8 @@ static int pl011_probe(struct amba_device *dev, const struct amba_id *id)
 	}
 
 	/* Ensure interrupts from this UART are masked and cleared */
-	writew(0, uap->port.membase + UART011_IMSC);
-	writew(0xffff, uap->port.membase + UART011_ICR);
+	writew(0, base + UART011_IMSC);
+	writew(0xffff, base + UART011_ICR);
 
 	uap->vendor = vendor;
 	uap->lcrh_rx = vendor->lcrh_rx;
Signature · 1 line
1.7.7.2
#1 lore raw
Quoted 9 lines · Alessandro Rubini

patch 9b96fba, currently in linux-next, clears interrupts using uap->port.membase that has not been assigned. ?My x86 system, that uses a pci-to-amba bridge, panics with a message like:

? BUG: unable to handle kernel NULL pointer dereference at 00000038 ? IP: [<c12c85ed>] pl011_probe+0x119/0x303

Signed-off-by Alessandro Rubini <[email protected]>
Acked-by Giancarlo Asnaghi <[email protected]>

Yep I know, already sent the remedy, just waiting for Greg to pick it up:
http://marc.info/?l=linux-serial&m=133235774423240&w=2

But thanks for the quick attention :-)

Yours,
Linus Walleij

#2 lore raw
In reply to Alessandro Rubini

Hello.

Quoted 1 line · Alessandro Rubini

patch 9b96fba, currently in linux-next, clears interrupts using

Please also specify the summary of this commit in parens.

Quoted 8 lines

uap->port.membase that has not been assigned. My x86 system, that uses a pci-to-amba bridge, panics with a message like:

    BUG: unable to handle kernel NULL pointer dereference at 00000038
    IP: [<c12c85ed>] pl011_probe+0x119/0x303
Signed-off-by Alessandro Rubini<[email protected]>
Acked-by Giancarlo Asnaghi<[email protected]>

WBR, Sergei