On 2018/8/2 2:58, Jaegeuk Kim wrote: > On 08/01, Chao Yu wrote: >> From: Chao Yu <yuch...@huawei.com> >> >> syzbot found the following crash on: >> >> HEAD commit: d9bd94c0bcaa Add linux-next specific files for 20180801 >> git tree: linux-next >> console output: https://syzkaller.appspot.com/x/log.txt?x=1001189c400000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=cc8964ea4d04518c >> dashboard link: https://syzkaller.appspot.com/bug?extid=c966a82db0b14aa37e81 >> compiler: gcc (GCC) 8.0.1 20180413 (experimental) >> >> Unfortunately, I don't have any reproducer for this crash yet. >> >> IMPORTANT: if you fix the bug, please add the following tag to the commit: >> Reported-by: syzbot+c966a82db0b14aa37...@syzkaller.appspotmail.com >> >> loop7: rw=12288, want=8200, limit=20 >> netlink: 65342 bytes leftover after parsing attributes in process >> `syz-executor4'. >> openvswitch: netlink: Message has 8 unknown bytes. >> kasan: CONFIG_KASAN_INLINE enabled >> kasan: GPF could be caused by NULL-ptr deref or user memory access >> general protection fault: 0000 [#1] SMP KASAN >> CPU: 1 PID: 7615 Comm: syz-executor7 Not tainted 4.18.0-rc7-next-20180801+ >> #29 >> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS >> Google 01/01/2011 >> RIP: 0010:__read_once_size include/linux/compiler.h:188 [inline] >> RIP: 0010:compound_head include/linux/page-flags.h:142 [inline] >> RIP: 0010:PageLocked include/linux/page-flags.h:272 [inline] >> RIP: 0010:f2fs_put_page fs/f2fs/f2fs.h:2011 [inline] >> RIP: 0010:validate_checkpoint+0x66d/0xec0 fs/f2fs/checkpoint.c:835 >> Code: e8 58 05 7f fe 4c 8d 6b 80 4d 8d 74 24 08 48 b8 00 00 00 00 00 fc ff >> df 4c 89 ea 48 c1 ea 03 c6 04 02 00 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f 85 >> f4 06 00 00 4c 89 ea 4d 8b 7c 24 08 48 b8 00 00 >> RSP: 0018:ffff8801937cebe8 EFLAGS: 00010246 >> RAX: dffffc0000000000 RBX: ffff8801937cef30 RCX: ffffc90006035000 >> RDX: 0000000000000000 RSI: ffffffff82fd9658 RDI: 0000000000000005 >> RBP: ffff8801937cef58 R08: ffff8801ab254700 R09: fffff94000d9e026 >> R10: fffff94000d9e026 R11: ffffea0006cf0137 R12: fffffffffffffffb >> R13: ffff8801937ceeb0 R14: 0000000000000003 R15: ffff880193419b40 >> FS: 00007f36a61d5700(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 00007fc04ff93000 CR3: 00000001d0562000 CR4: 00000000001426e0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> Call Trace: >> f2fs_get_valid_checkpoint+0x436/0x1ec0 fs/f2fs/checkpoint.c:860 >> f2fs_fill_super+0x2d42/0x8110 fs/f2fs/super.c:2883 >> mount_bdev+0x314/0x3e0 fs/super.c:1344 >> f2fs_mount+0x3c/0x50 fs/f2fs/super.c:3133 >> legacy_get_tree+0x131/0x460 fs/fs_context.c:729 >> vfs_get_tree+0x1cb/0x5c0 fs/super.c:1743 >> do_new_mount fs/namespace.c:2603 [inline] >> do_mount+0x6f2/0x1e20 fs/namespace.c:2927 >> ksys_mount+0x12d/0x140 fs/namespace.c:3143 >> __do_sys_mount fs/namespace.c:3157 [inline] >> __se_sys_mount fs/namespace.c:3154 [inline] >> __x64_sys_mount+0xbe/0x150 fs/namespace.c:3154 >> do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 >> entry_SYSCALL_64_after_hwframe+0x49/0xbe >> RIP: 0033:0x45943a >> Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 bd 8a fb ff c3 66 2e 0f >> 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff >> 0f 83 9a 8a fb ff c3 66 0f 1f 84 00 00 00 00 00 >> RSP: 002b:00007f36a61d4a88 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5 >> RAX: ffffffffffffffda RBX: 00007f36a61d4b30 RCX: 000000000045943a >> RDX: 00007f36a61d4ad0 RSI: 0000000020000100 RDI: 00007f36a61d4af0 >> RBP: 0000000020000100 R08: 00007f36a61d4b30 R09: 00007f36a61d4ad0 >> R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000013 >> R13: 0000000000000000 R14: 00000000004c8ea0 R15: 0000000000000000 >> Modules linked in: >> Dumping ftrace buffer: >> (ftrace buffer empty) >> ---[ end trace bd8550c129352286 ]--- >> RIP: 0010:__read_once_size include/linux/compiler.h:188 [inline] >> RIP: 0010:compound_head include/linux/page-flags.h:142 [inline] >> RIP: 0010:PageLocked include/linux/page-flags.h:272 [inline] >> RIP: 0010:f2fs_put_page fs/f2fs/f2fs.h:2011 [inline] >> RIP: 0010:validate_checkpoint+0x66d/0xec0 fs/f2fs/checkpoint.c:835 >> Code: e8 58 05 7f fe 4c 8d 6b 80 4d 8d 74 24 08 48 b8 00 00 00 00 00 fc ff >> df 4c 89 ea 48 c1 ea 03 c6 04 02 00 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f 85 >> f4 06 00 00 4c 89 ea 4d 8b 7c 24 08 48 b8 00 00 >> RSP: 0018:ffff8801937cebe8 EFLAGS: 00010246 >> RAX: dffffc0000000000 RBX: ffff8801937cef30 RCX: ffffc90006035000 >> RDX: 0000000000000000 RSI: ffffffff82fd9658 RDI: 0000000000000005 >> netlink: 65342 bytes leftover after parsing attributes in process >> `syz-executor4'. >> RBP: ffff8801937cef58 R08: ffff8801ab254700 R09: fffff94000d9e026 >> openvswitch: netlink: Message has 8 unknown bytes. >> R10: fffff94000d9e026 R11: ffffea0006cf0137 R12: fffffffffffffffb >> R13: ffff8801937ceeb0 R14: 0000000000000003 R15: ffff880193419b40 >> FS: 00007f36a61d5700(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000 >> CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 >> CR2: 00007fc04ff93000 CR3: 00000001d0562000 CR4: 00000000001426e0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 >> >> In validate_checkpoint(), if we failed to call get_checkpoint_version(), we >> will pass returned invalid page pointer into f2fs_put_page, cause accessing >> invalid memory, this patch tries to handle error path correctly to fix this >> issue. >> >> Signed-off-by: Chao Yu <yuch...@huawei.com> >> --- >> fs/f2fs/checkpoint.c | 12 ++++++------ >> 1 file changed, 6 insertions(+), 6 deletions(-) >> >> diff --git a/fs/f2fs/checkpoint.c b/fs/f2fs/checkpoint.c >> index 2cffc37e6c5b..861e61e08aa6 100644 >> --- a/fs/f2fs/checkpoint.c >> +++ b/fs/f2fs/checkpoint.c >> @@ -780,6 +780,7 @@ static int get_checkpoint_version(struct f2fs_sb_info >> *sbi, block_t cp_addr, >> >> crc_offset = le32_to_cpu((*cp_block)->checksum_offset); >> if (crc_offset > (blk_size - sizeof(__le32))) { >> + f2fs_put_page(*cp_page, 1); >> f2fs_msg(sbi->sb, KERN_WARNING, >> "invalid crc_offset: %zu", crc_offset); >> return -EINVAL; >> @@ -787,6 +788,7 @@ static int get_checkpoint_version(struct f2fs_sb_info >> *sbi, block_t cp_addr, >> >> crc = cur_cp_crc(*cp_block); >> if (!f2fs_crc_valid(sbi, crc, *cp_block, crc_offset)) { >> + f2fs_put_page(*cp_page, 1); >> f2fs_msg(sbi->sb, KERN_WARNING, "invalid crc value"); >> return -EINVAL; >> } >> @@ -806,14 +808,14 @@ static struct page *validate_checkpoint(struct >> f2fs_sb_info *sbi, >> err = get_checkpoint_version(sbi, cp_addr, &cp_block, >> &cp_page_1, version); >> if (err) >> - goto invalid_cp1; >> + return NULL; >> >> if (le32_to_cpu(cp_block->cp_pack_total_block_count) > >> sbi->log_blocks_per_seg) { >> f2fs_msg(sbi->sb, KERN_WARNING, >> "invalid cp_pack_total_block_count:%u", >> le32_to_cpu(cp_block->cp_pack_total_block_count)); >> - goto invalid_cp1; >> + goto invalid_cp; >> } >> pre_version = *version; >> >> @@ -821,7 +823,7 @@ static struct page *validate_checkpoint(struct >> f2fs_sb_info *sbi, >> err = get_checkpoint_version(sbi, cp_addr, &cp_block, >> &cp_page_2, version); >> if (err) >> - goto invalid_cp2; >> + goto invalid_cp; >> cur_version = *version; >> >> if (cur_version == pre_version) { >> @@ -829,9 +831,7 @@ static struct page *validate_checkpoint(struct >> f2fs_sb_info *sbi, >> f2fs_put_page(cp_page_2, 1); >> return cp_page_1; >> } >> -invalid_cp2: >> - f2fs_put_page(cp_page_2, 1); > > we need to put cp_page_2 above.
Yes, let me update it in v2. Thanks, > >> -invalid_cp1: >> +invalid_cp: >> f2fs_put_page(cp_page_1, 1); >> return NULL; >> } >> -- >> 2.18.0 ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ Linux-f2fs-devel mailing list Linux-f2fs-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel