Re: 2.6.17-rc1-mm2: badness in 3w_xxxx driver
From: Jeff Garzik
Date: Sun Apr 09 2006 - 15:12:40 EST
Andrew Morton wrote:
Nick Orlov <bugfixer@xxxxxxx> wrote:
The following patch: x86-kmap_atomic-debugging.patch exposed a badness
in 3w_xxx driver.
Sweet, thanks.
I'm getting a lot of:
Apr 9 13:00:04 nickolas kernel: kmap_atomic: local irqs are enabled while using KM_IRQn
Apr 9 13:00:04 nickolas kernel: <c0104103> show_trace+0x13/0x20 <c010412e> dump_stack+0x1e/0x20
Apr 9 13:00:04 nickolas kernel: <c01159c9> kmap_atomic+0x79/0xe0 <c028b885> tw_transfer_internal+0x85/0xa0
Apr 9 13:00:04 nickolas kernel: <c028ca7e> tw_interrupt+0x3fe/0x820 <c0143b9e> handle_IRQ_event+0x3e/0x80
Apr 9 13:00:04 nickolas kernel: <c0143c70> __do_IRQ+0x90/0x100 <c01057a6> do_IRQ+0x26/0x40
Apr 9 13:00:04 nickolas kernel: <c010396e> common_interrupt+0x1a/0x20 <c0101cdd> cpu_idle+0x4d/0xb0
Apr 9 13:00:04 nickolas kernel: <c010f2cc> start_secondary+0x24c/0x4b0 <00000000> 0x0
Apr 9 13:00:04 nickolas kernel: <c214ffb4> 0xc214ffb4
I'm running 32 bit kernel on AMD64x2 w/ HIGHMEM enabled.
I think this is an old bug since the 3w_xxxx.c has not been changed for
a long time (at least since 2.6.16-rc1-mm4).
Please let me know if you want me to try some patches.
From: Andrew Morton <akpm@xxxxxxxx>
We must disable local IRQs while holding KM_IRQ0 or KM_IRQ1. Otherwise, an
IRQ handler could use those kmap slots while this code is using them,
resulting in memory corruption.
Thanks to Nick Orlov <bugfixer@xxxxxxx> for reporting.
Cc: <linuxraid@xxxxxxxx>
Cc: James Bottomley <James.Bottomley@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
drivers/scsi/3w-xxxx.c | 3 +++
1 files changed, 3 insertions(+)
diff -puN drivers/scsi/3w-xxxx.c~3ware-kmap_atomic-fix drivers/scsi/3w-xxxx.c
--- devel/drivers/scsi/3w-xxxx.c~3ware-kmap_atomic-fix 2006-04-09 11:28:08.000000000 -0700
+++ devel-akpm/drivers/scsi/3w-xxxx.c 2006-04-09 11:29:21.000000000 -0700
@@ -1508,10 +1508,12 @@ static void tw_transfer_internal(TW_Devi
struct scsi_cmnd *cmd = tw_dev->srb[request_id];
void *buf;
unsigned int transfer_len;
+ unsigned long flags = 0;
if (cmd->use_sg) {
struct scatterlist *sg =
(struct scatterlist *)cmd->request_buffer;
+ local_irq_save(flags);
buf = kmap_atomic(sg->page, KM_IRQ0) + sg->offset;
transfer_len = min(sg->length, len);
} else {
@@ -1526,6 +1528,7 @@ static void tw_transfer_internal(TW_Devi
sg = (struct scatterlist *)cmd->request_buffer;
kunmap_atomic(buf - sg->offset, KM_IRQ0);
+ local_irq_restore(flags);
ACK.
Though please make sure the active maintainer is CC'd on this... There
is even a helpful MAINTAINERS entry for this driver.
Jeff
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