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From: Pavel Machek <pavel@ucw.cz>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-kernel@vger.kernel.org, stable@vger.kernel.org,
	Naohiro Aota <naohiro.aota@wdc.com>,
	Damien Le Moal <damien.lemoal@wdc.com>,
	Christoph Hellwig <hch@lst.de>,
	Johannes Thumshirn <johannes.thumshirn@wdc.com>,
	Jens Axboe <axboe@kernel.dk>
Subject: Re: [PATCH 4.19 13/35] null_blk: Fix zone size initialization
Date: Wed, 6 Jan 2021 13:54:49 +0100	[thread overview]
Message-ID: <20210106125449.GA7589@duo.ucw.cz> (raw)
In-Reply-To: <20210104155704.049016882@linuxfoundation.org>

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Hi!

> commit 0ebcdd702f49aeb0ad2e2d894f8c124a0acc6e23 upstream.
> 
> For a null_blk device with zoned mode enabled is currently initialized
> with a number of zones equal to the device capacity divided by the zone
> size, without considering if the device capacity is a multiple of the
> zone size. If the zone size is not a divisor of the capacity, the zones
> end up not covering the entire capacity, potentially resulting is out
> of bounds accesses to the zone array.
> 
> Fix this by adding one last smaller zone with a size equal to the
> remainder of the disk capacity divided by the zone size if the capacity
> is not a multiple of the zone size. For such smaller last zone, the zone
> capacity is also checked so that it does not exceed the smaller zone
> size.

> --- a/drivers/block/null_blk_zoned.c
> +++ b/drivers/block/null_blk_zoned.c
> @@ -1,9 +1,9 @@
>  // SPDX-License-Identifier: GPL-2.0
>  #include <linux/vmalloc.h>
> +#include <linux/sizes.h>
>  #include "null_blk.h"
>  
> -/* zone_size in MBs to sectors. */
> -#define ZONE_SIZE_SHIFT		11
> +#define MB_TO_SECTS(mb) (((sector_t)mb * SZ_1M) >> SECTOR_SHIFT)

This macro is quite dangerous. (mb) would help, but inline function
would be better.


> +	dev->nr_zones = dev_capacity_sects >> ilog2(dev->zone_size_sects);
> +	if (dev_capacity_sects & (dev->zone_size_sects - 1))
> +		dev->nr_zones++;

Is this same as nr_zones = DIV_ROUND_UP(dev_capacity_sects,
dev->zone_size_sects)? Would that be faster, more readable and robust
against weird dev->zone_size_sects sizes?

Best regards,
								Pavel
-- 
http://www.livejournal.com/~pavelmachek

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  reply	other threads:[~2021-01-06 12:56 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-01-04 15:57 [PATCH 4.19 00/35] 4.19.165-rc1 review Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 01/35] md/raid10: initialize r10_bio->read_slot before use Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 02/35] fscrypt: add fscrypt_is_nokey_name() Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 03/35] ext4: prevent creating duplicate encrypted filenames Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 04/35] f2fs: " Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 05/35] ubifs: " Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 06/35] vfio/pci: Move dummy_resources_list init in vfio_pci_probe() Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 07/35] ext4: dont remount read-only with errors=continue on reboot Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 08/35] uapi: move constants from <linux/kernel.h> to <linux/const.h> Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 09/35] KVM: SVM: relax conditions for allowing MSR_IA32_SPEC_CTRL accesses Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 10/35] KVM: x86: reinstate vendor-agnostic check on SPEC_CTRL cpuid bits Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 11/35] powerpc/bitops: Fix possible undefined behaviour with fls() and fls64() Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 12/35] xen/gntdev.c: Mark pages as dirty Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 13/35] null_blk: Fix zone size initialization Greg Kroah-Hartman
2021-01-06 12:54   ` Pavel Machek [this message]
2021-01-11  2:46     ` Damien Le Moal
2021-01-04 15:57 ` [PATCH 4.19 14/35] of: fix linker-section match-table corruption Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 15/35] asm-generic/tlb: Track freeing of page-table directories in struct mmu_gather Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 16/35] asm-generic/tlb: Track which levels of the page tables have been cleared Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 17/35] asm-generic/tlb, arch: Invert CONFIG_HAVE_RCU_TABLE_INVALIDATE Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 18/35] powerpc/mmu_gather: enable RCU_TABLE_FREE even for !SMP case Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 19/35] mm/mmu_gather: invalidate TLB correctly on batch allocation failure and flush Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 20/35] asm-generic/tlb: avoid potential double flush Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 21/35] Bluetooth: hci_h5: close serdev device and free hu in h5_close Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 22/35] reiserfs: add check for an invalid ih_entry_count Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 23/35] misc: vmw_vmci: fix kernel info-leak by initializing dbells in vmci_ctx_get_chkpt_doorbells() Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 24/35] media: gp8psk: initialize stats at power control logic Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 25/35] ALSA: seq: Use bool for snd_seq_queue internal flags Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 26/35] ALSA: rawmidi: Access runtime->avail always in spinlock Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 27/35] fcntl: Fix potential deadlock in send_sig{io, urg}() Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 28/35] rtc: sun6i: Fix memleak in sun6i_rtc_clk_init Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 29/35] module: set MODULE_STATE_GOING state when a module fails to load Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 30/35] quota: Dont overflow quota file offsets Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 31/35] powerpc: sysdev: add missing iounmap() on error in mpic_msgr_probe() Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 32/35] NFSv4: Fix a pNFS layout related use-after-free race when freeing the inode Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 33/35] module: delay kobject uevent until after module init call Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 34/35] ALSA: pcm: Clear the full allocated memory at hw_params Greg Kroah-Hartman
2021-01-04 15:57 ` [PATCH 4.19 35/35] dm verity: skip verity work if I/O error when system is shutting down Greg Kroah-Hartman
2021-01-04 17:43 ` [PATCH 4.19 00/35] 4.19.165-rc1 review Daniel Díaz
2021-01-05  9:06   ` Greg Kroah-Hartman
2021-01-04 19:59 ` Pavel Machek
2021-01-04 21:09 ` Jon Hunter
2021-01-05  1:58 ` Guenter Roeck
2021-01-05  9:06   ` Greg Kroah-Hartman
2021-01-05 16:44 ` Shuah Khan
2021-01-06 13:46   ` Greg Kroah-Hartman

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