Re: [PATCH] block: Avoid divide by 0 when max_discard_sectors is 0
David, On Tue, Dec 18, 2012 at 4:42 PM, David Rientjes wrote: > On Tue, 18 Dec 2012, Doug Anderson wrote: > >> The recent commit "block: discard granularity might not be power of 2" >> introduced a divide by 0 in the kernel. Previously the code didn't >> try to divide by discard_granularity when max_discard_sectors was 0. >> >> Fix the code to only do the division if max_discard_sectors is >> specified. >> > > Could you try Linus' patch at > http://marc.info/?l=linux-kernel=135584941732572 and give your Tested-by > if it solves your issue? Hoo boy. Thanks for the pointer. I missed that when searching to see if this had already been fixed. :( I'm pretty sure Linus's patch will fix my problem since I think my system has "max_discard_sectors" as 0 and his patch has the same effect as mine: avoid the divide by 0. Someone else will need to test his patch on a system that actually uses discard. In any case, I will test and send a Tested-by as soon as I'm able. Please consider my patch abandoned. > > Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] block: Avoid divide by 0 when max_discard_sectors is 0
On Tue, 18 Dec 2012, Doug Anderson wrote: > The recent commit "block: discard granularity might not be power of 2" > introduced a divide by 0 in the kernel. Previously the code didn't > try to divide by discard_granularity when max_discard_sectors was 0. > > Fix the code to only do the division if max_discard_sectors is > specified. > Could you try Linus' patch at http://marc.info/?l=linux-kernel=135584941732572 and give your Tested-by if it solves your issue? Thanks. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
[PATCH] block: Avoid divide by 0 when max_discard_sectors is 0
The recent commit "block: discard granularity might not be power of 2"
introduced a divide by 0 in the kernel. Previously the code didn't
try to divide by discard_granularity when max_discard_sectors was 0.
Fix the code to only do the division if max_discard_sectors is
specified.
Error looked like this:
Division by zero in kernel.
[<8001618c>] (unwind_backtrace+0x0/0xec) from [<8046cfac>]
(dump_stack+0x20/0x24)
[<8046cfac>] (dump_stack+0x20/0x24) from [<80012bf0>] (__div0+0x20/0x28)
[<80012bf0>] (__div0+0x20/0x28) from [<80224c24>] (Ldiv0_64+0x8/0x18)
[<80224c24>] (Ldiv0_64+0x8/0x18) from [<8021bcb8>] (add_partition+0x308/0x344)
[<8021bcb8>] (add_partition+0x308/0x344) from [<8021bf3c>]
(rescan_partitions+0x248/0x2b8)
[<8021bf3c>] (rescan_partitions+0x248/0x2b8) from [<80127ae4>]
(__blkdev_get+0x170/0x380)
[<80127ae4>] (__blkdev_get+0x170/0x380) from [<80127e60>]
(blkdev_get+0x16c/0x2d0)
[<80127e60>] (blkdev_get+0x16c/0x2d0) from [<8021984c>] (add_disk+0x284/0x42c)
[<8021984c>] (add_disk+0x284/0x42c) from [<80342f50>] (mmc_add_disk+0x28/0x100)
[<80342f50>] (mmc_add_disk+0x28/0x100) from [<8034392c>]
(mmc_blk_probe+0x2a8/0x2d8)
[<8034392c>] (mmc_blk_probe+0x2a8/0x2d8) from [<8033865c>]
(mmc_bus_probe+0x24/0x28)
[<8033865c>] (mmc_bus_probe+0x24/0x28) from [<802969d8>]
(driver_probe_device+0xb0/0x220)
[<802969d8>] (driver_probe_device+0xb0/0x220) from [<80296c1c>]
(__device_attach+0x38/0x54)
[<80296c1c>] (__device_attach+0x38/0x54) from [<80294da4>]
(bus_for_each_drv+0x5c/0xa4)
[<80294da4>] (bus_for_each_drv+0x5c/0xa4) from [<802968d0>]
(device_attach+0x78/0x9c)
[<802968d0>] (device_attach+0x78/0x9c) from [<80295df8>]
(bus_probe_device+0x38/0xa8)
[<80295df8>] (bus_probe_device+0x38/0xa8) from [<80294250>]
(device_add+0x43c/0x60c)
[<80294250>] (device_add+0x43c/0x60c) from [<80338b84>]
(mmc_add_card+0x18c/0x1e8)
[<80338b84>] (mmc_add_card+0x18c/0x1e8) from [<8033d414>]
(mmc_attach_sd+0x18c/0x214)
[<8033d414>] (mmc_attach_sd+0x18c/0x214) from [<803382b0>]
(mmc_rescan+0x25c/0x2c8)
[<803382b0>] (mmc_rescan+0x25c/0x2c8) from [<80042788>]
(process_one_work+0x228/0x408)
[<80042788>] (process_one_work+0x228/0x408) from [<80042df4>]
(worker_thread+0x280/0x3c4)
[<80042df4>] (worker_thread+0x280/0x3c4) from [<80048544>] (kthread+0xbc/0xcc)
[<80048544>] (kthread+0xbc/0xcc) from [<8000e358>] (ret_from_fork+0x14/0x20)
Signed-off-by: Doug Anderson
---
include/linux/blkdev.h |2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index acb4f7b..b35c7e9 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1189,11 +1189,11 @@ static inline int queue_discard_alignment(struct
request_queue *q)
static inline int queue_limit_discard_alignment(struct queue_limits *lim,
sector_t sector)
{
sector_t alignment = sector << 9;
- alignment = sector_div(alignment, lim->discard_granularity);
if (!lim->max_discard_sectors)
return 0;
+ alignment = sector_div(alignment, lim->discard_granularity);
alignment = lim->discard_granularity + lim->discard_alignment -
alignment;
return sector_div(alignment, lim->discard_granularity);
}
--
1.7.7.3
--
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Please read the FAQ at http://www.tux.org/lkml/
[PATCH] block: Avoid divide by 0 when max_discard_sectors is 0
The recent commit block: discard granularity might not be power of 2
introduced a divide by 0 in the kernel. Previously the code didn't
try to divide by discard_granularity when max_discard_sectors was 0.
Fix the code to only do the division if max_discard_sectors is
specified.
Error looked like this:
Division by zero in kernel.
[8001618c] (unwind_backtrace+0x0/0xec) from [8046cfac]
(dump_stack+0x20/0x24)
[8046cfac] (dump_stack+0x20/0x24) from [80012bf0] (__div0+0x20/0x28)
[80012bf0] (__div0+0x20/0x28) from [80224c24] (Ldiv0_64+0x8/0x18)
[80224c24] (Ldiv0_64+0x8/0x18) from [8021bcb8] (add_partition+0x308/0x344)
[8021bcb8] (add_partition+0x308/0x344) from [8021bf3c]
(rescan_partitions+0x248/0x2b8)
[8021bf3c] (rescan_partitions+0x248/0x2b8) from [80127ae4]
(__blkdev_get+0x170/0x380)
[80127ae4] (__blkdev_get+0x170/0x380) from [80127e60]
(blkdev_get+0x16c/0x2d0)
[80127e60] (blkdev_get+0x16c/0x2d0) from [8021984c] (add_disk+0x284/0x42c)
[8021984c] (add_disk+0x284/0x42c) from [80342f50] (mmc_add_disk+0x28/0x100)
[80342f50] (mmc_add_disk+0x28/0x100) from [8034392c]
(mmc_blk_probe+0x2a8/0x2d8)
[8034392c] (mmc_blk_probe+0x2a8/0x2d8) from [8033865c]
(mmc_bus_probe+0x24/0x28)
[8033865c] (mmc_bus_probe+0x24/0x28) from [802969d8]
(driver_probe_device+0xb0/0x220)
[802969d8] (driver_probe_device+0xb0/0x220) from [80296c1c]
(__device_attach+0x38/0x54)
[80296c1c] (__device_attach+0x38/0x54) from [80294da4]
(bus_for_each_drv+0x5c/0xa4)
[80294da4] (bus_for_each_drv+0x5c/0xa4) from [802968d0]
(device_attach+0x78/0x9c)
[802968d0] (device_attach+0x78/0x9c) from [80295df8]
(bus_probe_device+0x38/0xa8)
[80295df8] (bus_probe_device+0x38/0xa8) from [80294250]
(device_add+0x43c/0x60c)
[80294250] (device_add+0x43c/0x60c) from [80338b84]
(mmc_add_card+0x18c/0x1e8)
[80338b84] (mmc_add_card+0x18c/0x1e8) from [8033d414]
(mmc_attach_sd+0x18c/0x214)
[8033d414] (mmc_attach_sd+0x18c/0x214) from [803382b0]
(mmc_rescan+0x25c/0x2c8)
[803382b0] (mmc_rescan+0x25c/0x2c8) from [80042788]
(process_one_work+0x228/0x408)
[80042788] (process_one_work+0x228/0x408) from [80042df4]
(worker_thread+0x280/0x3c4)
[80042df4] (worker_thread+0x280/0x3c4) from [80048544] (kthread+0xbc/0xcc)
[80048544] (kthread+0xbc/0xcc) from [8000e358] (ret_from_fork+0x14/0x20)
Signed-off-by: Doug Anderson diand...@chromium.org
---
include/linux/blkdev.h |2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index acb4f7b..b35c7e9 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1189,11 +1189,11 @@ static inline int queue_discard_alignment(struct
request_queue *q)
static inline int queue_limit_discard_alignment(struct queue_limits *lim,
sector_t sector)
{
sector_t alignment = sector 9;
- alignment = sector_div(alignment, lim-discard_granularity);
if (!lim-max_discard_sectors)
return 0;
+ alignment = sector_div(alignment, lim-discard_granularity);
alignment = lim-discard_granularity + lim-discard_alignment -
alignment;
return sector_div(alignment, lim-discard_granularity);
}
--
1.7.7.3
--
To unsubscribe from this list: send the line unsubscribe linux-kernel in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] block: Avoid divide by 0 when max_discard_sectors is 0
On Tue, 18 Dec 2012, Doug Anderson wrote: The recent commit block: discard granularity might not be power of 2 introduced a divide by 0 in the kernel. Previously the code didn't try to divide by discard_granularity when max_discard_sectors was 0. Fix the code to only do the division if max_discard_sectors is specified. Could you try Linus' patch at http://marc.info/?l=linux-kernelm=135584941732572 and give your Tested-by if it solves your issue? Thanks. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH] block: Avoid divide by 0 when max_discard_sectors is 0
David, On Tue, Dec 18, 2012 at 4:42 PM, David Rientjes rient...@google.com wrote: On Tue, 18 Dec 2012, Doug Anderson wrote: The recent commit block: discard granularity might not be power of 2 introduced a divide by 0 in the kernel. Previously the code didn't try to divide by discard_granularity when max_discard_sectors was 0. Fix the code to only do the division if max_discard_sectors is specified. Could you try Linus' patch at http://marc.info/?l=linux-kernelm=135584941732572 and give your Tested-by if it solves your issue? Hoo boy. Thanks for the pointer. I missed that when searching to see if this had already been fixed. :( I'm pretty sure Linus's patch will fix my problem since I think my system has max_discard_sectors as 0 and his patch has the same effect as mine: avoid the divide by 0. Someone else will need to test his patch on a system that actually uses discard. In any case, I will test and send a Tested-by as soon as I'm able. Please consider my patch abandoned. Thanks. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
