On Wed, Jul 23, 2025 at 11:42 AM Joanne Koong <joannelkoong@xxxxxxxxx> wrote: > > On Wed, Jul 23, 2025 at 7:46 AM Darrick J. Wong <djwong@xxxxxxxxxx> wrote: > > > > [cc Joanne] > > > > On Wed, Jul 23, 2025 at 05:14:28PM +0530, Naresh Kamboju wrote: > > > Regressions found while running LTP msync04 tests on qemu-arm64 running > > > Linux next-20250721, next-20250722 and next-20250723 with 16K and 64K > > > page size enabled builds. > > > > > > CONFIG_ARM64_64K_PAGES=y ( kernel warning as below ) > > > CONFIG_ARM64_16K_PAGES=y ( kernel warning as below ) > > > > > > No warning noticed with 4K page size. > > > CONFIG_ARM64_4K_PAGES=y works as expected > > > > You might want to cc Joanne since she's been working on large folio > > support in fuse. > > > > > First seen on the tag next-20250721. > > > Good: next-20250718 > > > Bad: next-20250721 to next-20250723 > > Thanks for the report. Is there a link to the script that mounts the > fuse server for these tests? I'm curious whether this was mounted as a > fuseblk filesystem. > > > > > > > Regression Analysis: > > > - New regression? Yes > > > - Reproducibility? Yes > > > > > > Test regression: next-20250721 arm64 16K and 64K page size WARNING fs > > > fuse file.c at fuse_iomap_writeback_range > > > > > > Reported-by: Linux Kernel Functional Testing <lkft@xxxxxxxxxx> > > > > > > ## Test log > > > ------------[ cut here ]------------ > > > [ 343.828105] WARNING: fs/fuse/file.c:2146 at > > > fuse_iomap_writeback_range+0x478/0x558 [fuse], CPU#0: msync04/4190 > > > > WARN_ON_ONCE(len & (PAGE_SIZE - 1)); > > > > /me speculates that this might be triggered by an attempt to write back > > some 4k fsblock within a 16/64k base page? > > > > I think this can happen on 4k base pages as well actually. On the > iomap side, the length passed is always block-aligned and in fuse, we > set blkbits to be PAGE_SHIFT so theoretically block-aligned is always > page-aligned, but I missed that if it's a "fuseblk" filesystem, that > isn't true and the blocksize is initialized to a default size of 512 > or whatever block size is passed in when it's mounted. > > I'll send out a patch to remove this line. It doesn't make any > difference for fuse_iomap_writeback_range() logic whether len is > page-aligned or not; I had added it as a sanity-check against sketchy > ranges. > https://lore.kernel.org/linux-fsdevel/20250723230850.2395561-1-joannelkoong@xxxxxxxxx/T/#u is the patch for removing this
