ntfs_trim_fs() should loop with wnd->nwnd, not wnd->nbits. KASAN detects this as an out-of-bounds access like below: ================================================================== BUG: KASAN: slab-out-of-bounds in ntfs_trim_fs (fs/ntfs3/bitmap.c:1434) Read of size 2 at addr ffff8881745b4f02 by task repro/19678 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-2.fc37 04/01/2014 Call Trace: <TASK> dump_stack_lvl (lib/dump_stack.c:107 (discriminator 4)) print_report (mm/kasan/report.c:285 mm/kasan/report.c:395) ? __virt_addr_valid (arch/x86/mm/physaddr.c:66) ? __phys_addr (arch/x86/mm/physaddr.c:32 (discriminator 4)) ? ntfs_trim_fs (fs/ntfs3/bitmap.c:1434) ? ntfs_trim_fs (fs/ntfs3/bitmap.c:1434) kasan_report (mm/kasan/report.c:162 mm/kasan/report.c:497) ? ntfs_trim_fs (fs/ntfs3/bitmap.c:1434) ntfs_trim_fs (fs/ntfs3/bitmap.c:1434) ntfs_ioctl (fs/ntfs3/file.c:41 fs/ntfs3/file.c:57) ? ntfs_fiemap (fs/ntfs3/file.c:51) ? bpf_lsm_file_ioctl (./include/linux/lsm_hook_defs.h:165) ? ntfs_fiemap (fs/ntfs3/file.c:51) __x64_sys_ioctl (fs/ioctl.c:52 fs/ioctl.c:870 fs/ioctl.c:856 fs/ioctl.c:856) do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) Signed-off-by: Shigeru Yoshida <syoshida@xxxxxxxxxx> --- fs/ntfs3/bitmap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/ntfs3/bitmap.c b/fs/ntfs3/bitmap.c index e92bbd754365..1930640be31a 100644 --- a/fs/ntfs3/bitmap.c +++ b/fs/ntfs3/bitmap.c @@ -1424,7 +1424,7 @@ int ntfs_trim_fs(struct ntfs_sb_info *sbi, struct fstrim_range *range) down_read_nested(&wnd->rw_lock, BITMAP_MUTEX_CLUSTERS); - for (; iw < wnd->nbits; iw++, wbit = 0) { + for (; iw < wnd->nwnd; iw++, wbit = 0) { CLST lcn_wnd = iw * wbits; struct buffer_head *bh; -- 2.38.1