On Tue, Sep 01, 2020 at 05:58:29PM +0200, Bodo Stroesser wrote:
On 2020-09-01 16:02, Greg KH wrote:
On Fri, Aug 28, 2020 at 12:03:38PM +0200, Bodo Stroesser wrote:
Hi, I'm adding stable@vger.kernel.org
Once again, this time really adding stable.
On 2020-06-03 04:31, Martin K. Petersen wrote:
On Thu, 28 May 2020 21:31:08 +0200, Bodo Stroesser wrote:
- If remaining ring space before the end of the ring is smaller then the next cmd to write, tcmu writes a padding entry which fills the remaining space at the end of the ring. Then tcmu calls tcmu_flush_dcache_range() with the size of struct tcmu_cmd_entry as data length to flush. If the space filled by the padding was smaller then tcmu_cmd_entry, tcmu_flush_dcache_range() is called for an address range reaching behind the end of the vmalloc'ed ring. tcmu_flush_dcache_range() in a loop calls flush_dcache_page(virt_to_page(start)); for every page being part of the range. On x86 the line is optimized out by the compiler, as flush_dcache_page() is empty on x86. But I assume the above can cause trouble on other architectures that really have a flush_dcache_page(). For paddings only the header part of an entry is relevant Due to alignment rules the header always fits in the remaining space, if padding is needed. So tcmu_flush_dcache_range() can safely be called with sizeof(entry->hdr) as the length here.
[...]
Applied to 5.8/scsi-queue, thanks!
[1/1] scsi: target: tcmu: Fix size in calls to tcmu_flush_dcache_range https://git.kernel.org/mkp/scsi/c/8c4e0f212398
The full commit of this patch is: 8c4e0f212398cdd1eb4310a5981d06a723cdd24f
This patch is the first of four patches that are necessary to run tcmu on ARM without crash. For details please see https://bugzilla.kernel.org/show_bug.cgi?id=208045 Upsteam commits of patches 2,3, and 4 are: 2: 3c58f737231e "scsi: target: tcmu: Optimize use of flush_dcache_page" 3: 3145550a7f8b "scsi: target: tcmu: Fix crash in tcmu_flush_dcache_range on ARM" 4: 5a0c256d96f0 "scsi: target: tcmu: Fix crash on ARM during cmd completion"
Since patches 3 and 4 already were accepted for 5.8, 5.4, and 4.19, and I sent a request to add patch 2 about 1 hour ago, please consider adding this patch to 5.4 and 4.19, because without it tcmu on ARM will still crash.
I don't see such a request, and am confused now.
What exact commits do you want backported, and to what trees?
thanks,
greg k-h
Sorry for the confusion.
The subject of the request I mentioned is "Re: [PATCH v2 0/2] scsi: target: tcmu: fix crashes on ARM" because it is for the first patch of a small series of two.
Please backport to kernels 4.19 and 5.4 (it is part of 5.8 from beginning): 8c4e0f212398 "scsi: target: tcmu: fix size in calls to tcmu_flush_dcache_range"
Please backport to kernels 4.19, 5.4 and 5.8: 3c58f737231e "scsi: target: tcmu: Optimize use of flush_dcache_page"
Backporting to 4.14 or earlier AFAICS would need more work, especially testing. I don't think that its worth it.
Thanks, both now queued up.
greg k-h