ci starts bisection 2022-11-12 15:22:34.328485594 +0000 UTC m=+171118.386009568 bisecting cause commit starting from f8f60f322f0640c8edda2942ca5f84b7a27c417a building syzkaller on 3ead01ade920906b89aff0066a9d5e922ee270c8 ensuring issue is reproducible on original commit f8f60f322f0640c8edda2942ca5f84b7a27c417a testing commit f8f60f322f0640c8edda2942ca5f84b7a27c417a gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 6cdda718c437dde53ad608a950e35ce66d3281caa22e61897691b675f4fdda49 all runs: crashed: KASAN: stack-out-of-bounds Read in collapse_file testing release v6.0 testing commit 4fe89d07dcc2804c8b562f6c7896a45643d34b2f gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 0de1de9ead4ba5e6056c5c52a2416f79211bf8f1dbc77c8b290c91d07662077a failed: failed to create VM pool: failed to create GCE image: create image operation failed: &{Code:PERMISSIONS_ERROR ErrorDetails:[] Location: Message:Required 'read' permission for 'disks/ci-upstream-linux-next-kasan-gce-root-bisect-job-bisect-job-image.tar.gz' ForceSendFields:[] NullFields:[]}. testing release v5.19 testing commit 3d7cb6b04c3f3115719235cc6866b10326de34cd gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: e29077be8193f10107ca99b89bfd1b8640ebf046462634adb120858a20538351 all runs: OK # git bisect start f8f60f322f0640c8edda2942ca5f84b7a27c417a 3d7cb6b04c3f3115719235cc6866b10326de34cd Bisecting: 19085 revisions left to test after this (roughly 14 steps) [6ec6368edb468bae8082dd3507115b0f6448d587] Bluetooth: btusb: Add debug message for CSR controllers testing commit 6ec6368edb468bae8082dd3507115b0f6448d587 gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: a224321dc9cc17c781ef86740e1fb8894ff0abfbde84171af38996e77e1ae3eb all runs: OK # git bisect good 6ec6368edb468bae8082dd3507115b0f6448d587 Bisecting: 9550 revisions left to test after this (roughly 13 steps) [95b8b5953a315081eadbadf49200e57d7e05aae7] Merge tag 'loongarch-6.1' of git://git.kernel.org/pub/scm/linux/kernel/git/chenhuacai/linux-loongson testing commit 95b8b5953a315081eadbadf49200e57d7e05aae7 gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 62597cfaa39d74926353a55d9e3afe92d6dab6c593ae69a49c623cb66b8052e4 all runs: boot failed: WARNING in cpumask_next_wrap # git bisect skip 95b8b5953a315081eadbadf49200e57d7e05aae7 Bisecting: 9550 revisions left to test after this (roughly 13 steps) [61775d54d674ff8ec3658495e0dbc537227dc5c1] i2c: qcom-cci: Fix ordering of pm_runtime_xx and i2c_add_adapter testing commit 61775d54d674ff8ec3658495e0dbc537227dc5c1 gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 604043b91b17b2f36cc1ccab4e6adf6549014e56d5d7b378897411acee0aa6ce all runs: boot failed: WARNING in __netif_set_xps_queue # git bisect skip 61775d54d674ff8ec3658495e0dbc537227dc5c1 Bisecting: 9550 revisions left to test after this (roughly 13 steps) [710080a3794bed269533093f5d2d9e37908962f0] drm/amd/display: Remove some unused definitions from DCN32/321 testing commit 710080a3794bed269533093f5d2d9e37908962f0 gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 40fb380ab62b72ae6bdae0b5e52a2196025eae7fee3925d2211cfd7e3f63f73d all runs: OK # git bisect good 710080a3794bed269533093f5d2d9e37908962f0 Bisecting: 9162 revisions left to test after this (roughly 13 steps) [1fcc064b305a1aadeff0d4bff961094d27660acd] netfilter: rpfilter/fib: Set ->flowic_uid correctly for user namespaces. testing commit 1fcc064b305a1aadeff0d4bff961094d27660acd gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 5265fe603ab5a3d1d1bcbfc3c6ee4be87ed14b008c22d75db3e37c82b5c05f3c all runs: boot failed: WARNING in cpumask_next_wrap # git bisect skip 1fcc064b305a1aadeff0d4bff961094d27660acd Bisecting: 9162 revisions left to test after this (roughly 13 steps) [9a9a5d80ec9887814042c69768c2fee7961db7f4] MAINTAINERS: git://github -> https://github.com for petkan testing commit 9a9a5d80ec9887814042c69768c2fee7961db7f4 gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: b642c18e6dc16c69f29f7cafd84104ac9ab04c30c6b539c8204ed22d6b06b600 all runs: boot failed: WARNING in cpumask_next_wrap # git bisect skip 9a9a5d80ec9887814042c69768c2fee7961db7f4 Bisecting: 9162 revisions left to test after this (roughly 13 steps) [62158055c622154528d9653b8749cabf874bbef3] mmc: omap_hsmmc: fix return value check of mmc_add_host() testing commit 62158055c622154528d9653b8749cabf874bbef3 gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: fde5b81e7aab56530f12abd6225dc956a5e55ed926b5dbdd12dd51e1a3d9c2d3 all runs: OK # git bisect good 62158055c622154528d9653b8749cabf874bbef3 Bisecting: 3892 revisions left to test after this (roughly 12 steps) [66500d0e2e5c9b64fc5d3f4879e2140572e1b386] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git testing commit 66500d0e2e5c9b64fc5d3f4879e2140572e1b386 gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 21c8986448e6e24f6f2132c9958e7ba4ad5bbb1e0f2608591304db234cfec172 all runs: OK # git bisect good 66500d0e2e5c9b64fc5d3f4879e2140572e1b386 Bisecting: 2003 revisions left to test after this (roughly 11 steps) [080c1179d77ad36d6e51469b68801ef341ec292a] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git testing commit 080c1179d77ad36d6e51469b68801ef341ec292a gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: c242e707ec3ae45297b6685b9b2ed6015602b44ce5d5ed7b48599c87f12b69fb all runs: OK # git bisect good 080c1179d77ad36d6e51469b68801ef341ec292a Bisecting: 974 revisions left to test after this (roughly 10 steps) [84e5ca9988b4ee4351b068c7bb7152f4240054d4] Merge branch 'staging-next' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/staging.git testing commit 84e5ca9988b4ee4351b068c7bb7152f4240054d4 gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 974288b83d787806dfdb7ef88e60978ba68887ea2d65a2b5ec6f599cd43cc0af all runs: OK # git bisect good 84e5ca9988b4ee4351b068c7bb7152f4240054d4 Bisecting: 483 revisions left to test after this (roughly 9 steps) [917d2dd3c9cb80646df958c9a29b4ea1739cf4bd] Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git testing commit 917d2dd3c9cb80646df958c9a29b4ea1739cf4bd gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: bf876b244409802af52eeda408cfe31b08caf658bfbbbd9d595984fc8f166cc3 all runs: OK # git bisect good 917d2dd3c9cb80646df958c9a29b4ea1739cf4bd Bisecting: 256 revisions left to test after this (roughly 8 steps) [ca77a205798d441462bde61bfed6eaea86b31ecc] mm: vmscan: fix extreme overreclaim and swap floods testing commit ca77a205798d441462bde61bfed6eaea86b31ecc gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 6bcc71769462e204e8df294f784ac52a8a2b737b54c431c9d866ae4316f833f3 all runs: crashed: KASAN: stack-out-of-bounds Read in collapse_file # git bisect bad ca77a205798d441462bde61bfed6eaea86b31ecc Bisecting: 112 revisions left to test after this (roughly 7 steps) [b112efa5f46f7092111696cd63702ebd3776c82e] devdax: use dax_insert_entry() + dax_delete_mapping_entry() testing commit b112efa5f46f7092111696cd63702ebd3776c82e gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 479f95fc1df67f9cb9caead3e585dc0ef31972564b4732eb71276a49bd2ebae8 all runs: OK # git bisect good b112efa5f46f7092111696cd63702ebd3776c82e Bisecting: 55 revisions left to test after this (roughly 6 steps) [96ba188c569498fa3a5f4008c99307c802af9f01] mm/damon/sysfs: implement DAMOS tried regions update command testing commit 96ba188c569498fa3a5f4008c99307c802af9f01 gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: eef01b84bf2c340f5ae828cdda0bf6a03e96e25593b8a648dfe128eb3397a3b5 all runs: OK # git bisect good 96ba188c569498fa3a5f4008c99307c802af9f01 Bisecting: 27 revisions left to test after this (roughly 5 steps) [97f1b5e86a5aba85b339dcf55dc168c754be3354] mm/autonuma: use can_change_(pte|pmd)_writable() to replace savedwrite testing commit 97f1b5e86a5aba85b339dcf55dc168c754be3354 gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 2b5f0cd11dc6851fb92de0670fab24443fac9155537b46aaaf065e93b2ccf0ee all runs: crashed: KASAN: stack-out-of-bounds Read in collapse_file # git bisect bad 97f1b5e86a5aba85b339dcf55dc168c754be3354 Bisecting: 13 revisions left to test after this (roughly 4 steps) [02e4060f10a98bcd1a676e6dbf3fada156dcca3c] mm,thp,rmap: lock_compound_mapcounts() on THP mapcounts testing commit 02e4060f10a98bcd1a676e6dbf3fada156dcca3c gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: b5bf8b0e9ab5ff58e9185eab5807bf4c31a5dc0de6ab2a36da3f2deb552677fa all runs: OK # git bisect good 02e4060f10a98bcd1a676e6dbf3fada156dcca3c Bisecting: 6 revisions left to test after this (roughly 3 steps) [a0157a2c735bd9c8ea8486b2f3631225a086fe9d] mm/khugepaged: recover from poisoned file-backed memory testing commit a0157a2c735bd9c8ea8486b2f3631225a086fe9d gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 4ff52109835ff4d4a07255bad55405c2367c64d3f124d1662db83f359ad642ed all runs: crashed: KASAN: stack-out-of-bounds Read in collapse_file # git bisect bad a0157a2c735bd9c8ea8486b2f3631225a086fe9d Bisecting: 3 revisions left to test after this (roughly 2 steps) [2220e3a8953e86b87adfc753fc57c2a5e0b0a032] mm: anonymous shared memory naming testing commit 2220e3a8953e86b87adfc753fc57c2a5e0b0a032 gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 7a7216557edd3094c03e9d18d17012813a5656d40d03ab4d003e71624bda03e2 all runs: OK # git bisect good 2220e3a8953e86b87adfc753fc57c2a5e0b0a032 Bisecting: 1 revision left to test after this (roughly 1 step) [74b08da248b708ed8becf2e894be237a560cb3f6] mm-hugetlb_vmemmap-remap-head-page-to-newly-allocated-page-v3 testing commit 74b08da248b708ed8becf2e894be237a560cb3f6 gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: 5dae7a9feb87123525cc6088b0b14782f1fc4a6e4ef769ebf2dd140bb56657b9 all runs: OK # git bisect good 74b08da248b708ed8becf2e894be237a560cb3f6 Bisecting: 0 revisions left to test after this (roughly 0 steps) [b33939dc235e3c6371de48d02dbd3a617fae3c06] mm/khugepaged: recover from poisoned anonymous memory testing commit b33939dc235e3c6371de48d02dbd3a617fae3c06 gcc compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 kernel signature: f24f32f162ed707f27a99e290e030d783aea72fd4d7b4e7b3543eb0357ca3585 all runs: OK # git bisect good b33939dc235e3c6371de48d02dbd3a617fae3c06 a0157a2c735bd9c8ea8486b2f3631225a086fe9d is the first bad commit commit a0157a2c735bd9c8ea8486b2f3631225a086fe9d Author: Jiaqi Yan Date: Sun Nov 6 18:53:59 2022 -0800 mm/khugepaged: recover from poisoned file-backed memory Make collapse_file roll back when copying pages failed. More concretely: - extract copying operations into a separate loop - postpone the updates for nr_none until both scanning and copying succeeded - postpone joining small xarray entries until both scanning and copying succeeded - postpone the update operations to NR_XXX_THPS until both scanning and copying succeeded - for non-SHMEM file, roll back filemap_nr_thps_inc if scan succeeded but copying failed Tested manually: 0. Enable khugepaged on system under test. Mount tmpfs at /mnt/ramdisk. 1. Start a two-thread application. Each thread allocates a chunk of non-huge memory buffer from /mnt/ramdisk. 2. Pick 4 random buffer address (2 in each thread) and inject uncorrectable memory errors at physical addresses. 3. Signal both threads to make their memory buffer collapsible, i.e. calling madvise(MADV_HUGEPAGE). 4. Wait and then check kernel log: khugepaged is able to recover from poisoned pages by skipping them. 5. Signal both thread to inspect their buffer contents and make sure no data corruption. Link: https://lkml.kernel.org/r/20221107025359.2911028-3-jiaqiyan@google.com Signed-off-by: Jiaqi Yan Cc: Kirill A. Shutemov Cc: Miaohe Lin Cc: Naoya Horiguchi Cc: Oscar Salvador Cc: Tong Tiangen Cc: Tony Luck Cc: Yang Shi Signed-off-by: Andrew Morton mm/khugepaged.c | 74 +++++++++++++++++++++++++++++++++++---------------------- 1 file changed, 45 insertions(+), 29 deletions(-) culprit signature: 4ff52109835ff4d4a07255bad55405c2367c64d3f124d1662db83f359ad642ed parent signature: f24f32f162ed707f27a99e290e030d783aea72fd4d7b4e7b3543eb0357ca3585 revisions tested: 23, total time: 5h54m21.115445368s (build: 2h51m52.137619098s, test: 2h59m18.229326825s) first bad commit: a0157a2c735bd9c8ea8486b2f3631225a086fe9d mm/khugepaged: recover from poisoned file-backed memory recipients (to): ["akpm@linux-foundation.org" "akpm@linux-foundation.org" "jiaqiyan@google.com" "linux-mm@kvack.org"] recipients (cc): ["linux-kernel@vger.kernel.org"] crash: KASAN: stack-out-of-bounds Read in collapse_file ================================================================== BUG: KASAN: stack-out-of-bounds in collapse_file+0x3543/0x3f00 mm/khugepaged.c:2038 Read of size 8 at addr ffffc90004dd7910 by task syz-executor.0/4151 CPU: 1 PID: 4151 Comm: syz-executor.0 Not tainted 6.1.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x57/0x7d lib/dump_stack.c:106 print_address_description mm/kasan/report.c:253 [inline] print_report+0x15e/0x45d mm/kasan/report.c:364 kasan_report+0xbb/0x1f0 mm/kasan/report.c:464 collapse_file+0x3543/0x3f00 mm/khugepaged.c:2038 hpage_collapse_scan_file+0x97c/0x1190 mm/khugepaged.c:2237 madvise_collapse+0x43b/0x920 mm/khugepaged.c:2696 madvise_vma_behavior+0x5af/0x1670 mm/madvise.c:1073 madvise_walk_vmas+0x155/0x230 mm/madvise.c:1247 do_madvise.part.0+0x1c3/0x280 mm/madvise.c:1426 do_madvise mm/madvise.c:1439 [inline] __do_sys_madvise mm/madvise.c:1439 [inline] __se_sys_madvise mm/madvise.c:1437 [inline] __x64_sys_madvise+0xcc/0x130 mm/madvise.c:1437 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f5b0688b639 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f5b07539168 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007f5b069abf80 RCX: 00007f5b0688b639 RDX: 0000000000000019 RSI: 0000000000600003 RDI: 0000000020000000 RBP: 00007f5b068e67e1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffdb99226cf R14: 00007f5b07539300 R15: 0000000000022000 The buggy address belongs to stack of task syz-executor.0/4151 and is located at offset 120 in frame: collapse_file+0x0/0x3f00 arch/x86/include/asm/bitops.h:207 This frame has 4 objects: [32, 40) 'hpage' [64, 72) 'folio' [96, 112) 'pagelist' [128, 184) 'xas' The buggy address belongs to the virtual mapping at [ffffc90004dd0000, ffffc90004dd9000) created by: kernel_clone+0xb8/0x710 kernel/fork.c:2690 The buggy address belongs to the physical page: page:ffffea0001f03980 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7c0e6 memcg:ffff888145f32b82 flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff) raw: 00fff00000000000 0000000000000000 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000000000 00000001ffffffff ffff888145f32b82 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0x102dc2(GFP_HIGHUSER|__GFP_NOWARN|__GFP_ZERO), pid 4082, tgid 4082 (dhcpcd-run-hook), ts 68009043381, free_ts 68007595626 prep_new_page mm/page_alloc.c:2561 [inline] get_page_from_freelist+0x10b5/0x2d50 mm/page_alloc.c:4310 __alloc_pages+0x1c7/0x5a0 mm/page_alloc.c:5577 vm_area_alloc_pages mm/vmalloc.c:2989 [inline] __vmalloc_area_node mm/vmalloc.c:3057 [inline] __vmalloc_node_range+0x70e/0x1010 mm/vmalloc.c:3227 alloc_thread_stack_node kernel/fork.c:311 [inline] dup_task_struct kernel/fork.c:984 [inline] copy_process+0x52d/0x6810 kernel/fork.c:2103 kernel_clone+0xb8/0x710 kernel/fork.c:2690 __do_sys_clone+0xa1/0xe0 kernel/fork.c:2831 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd page last free stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1468 [inline] free_pcp_prepare+0x65c/0xc00 mm/page_alloc.c:1518 free_unref_page_prepare mm/page_alloc.c:3409 [inline] free_unref_page_list+0x172/0xc40 mm/page_alloc.c:3551 release_pages+0x24f/0xef0 mm/swap.c:1066 tlb_batch_pages_flush+0x85/0x160 mm/mmu_gather.c:59 tlb_flush_mmu_free mm/mmu_gather.c:256 [inline] tlb_flush_mmu mm/mmu_gather.c:263 [inline] tlb_finish_mmu+0x110/0x6c0 mm/mmu_gather.c:363 exit_mmap+0x1c9/0x610 mm/mmap.c:3105 __mmput+0xf3/0x440 kernel/fork.c:1204 exit_mm kernel/exit.c:516 [inline] do_exit+0x86f/0x2410 kernel/exit.c:807 do_group_exit+0xb0/0x250 kernel/exit.c:950 __do_sys_exit_group kernel/exit.c:961 [inline] __se_sys_exit_group kernel/exit.c:959 [inline] __x64_sys_exit_group+0x35/0x40 kernel/exit.c:959 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Memory state around the buggy address: ffffc90004dd7800: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffc90004dd7880: 00 00 00 f1 f1 f1 f1 00 f2 f2 f2 00 f2 f2 f2 00 >ffffc90004dd7900: 00 f2 f2 00 00 00 00 00 00 00 f3 f3 f3 f3 f3 00 ^ ffffc90004dd7980: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffc90004dd7a00: 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00 00 00 00 ==================================================================