9fd62605bb
Configure io_bits with 2 and enable LFS mode, generic/017 reports below dmesg: BUG: unable to handle kernel NULL pointer dereference at 00000039 *pdpt = 000000002fcb2001 *pde = 0000000000000000 Oops: 0000 [#1] PREEMPT SMP Modules linked in: crc32_generic zram f2fs(O) bnep rfcomm bluetooth ecdh_generic snd_intel8x0 snd_ac97_codec ac97_bus snd_pcm snd_seq_midi snd_seq_midi_event snd_rawmidi pcbc snd_seq joydev aesni_intel aes_i586 snd_seq_device snd_timer crypto_simd cryptd snd soundcore i2c_piix4 serio_raw mac_hid video parport_pc ppdev lp parport hid_generic usbhid psmouse hid e1000 CPU: 2 PID: 20779 Comm: xfs_io Tainted: G O 4.17.0-rc2 #38 Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 EIP: is_checkpointed_data+0x84/0xd0 [f2fs] EFLAGS: 00010207 CPU: 2 EAX: 00000000 EBX: f5cd7000 ECX: fffffe32 EDX: 00000039 ESI: 000001cd EDI: ec95fb6c EBP: e264bd80 ESP: e264bd6c DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 CR0: 80050033 CR2: 00000039 CR3: 2fe55660 CR4: 000406f0 Call Trace: __exchange_data_block+0xb3f/0x1000 [f2fs] f2fs_fallocate+0xab9/0x16b0 [f2fs] vfs_fallocate+0x17c/0x2d0 ksys_fallocate+0x42/0x70 sys_fallocate+0x31/0x40 do_fast_syscall_32+0xaa/0x22c entry_SYSENTER_32+0x4c/0x7b EIP: 0xb7f98c51 EFLAGS: 00000293 CPU: 2 EAX: ffffffda EBX: 00000003 ECX: 00000008 EDX: 01001000 ESI: 00000000 EDI: 00001000 EBP: 00000000 ESP: bfc0357c DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b Code: 00 00 d3 e8 8b 4d ec 2b 02 8b 55 f0 6b c0 1c 03 41 70 29 d6 8b 93 d0 06 00 00 8b 40 0c 83 ea 01 21 d6 89 f2 89 f1 c1 ea 03 f7 d1 <0f> be 14 10 83 e1 07 b8 01 00 00 00 d3 e0 85 c2 89 f8 0f 95 c3 EIP: is_checkpointed_data+0x84/0xd0 [f2fs] SS:ESP: 0068:e264bd6c CR2: 0000000000000039 ---[ end trace 9a4d4087cce6080a ]--- This is because in recovery flow of __exchange_data_block, we didn't pass olen to __roll_back_blkaddrs, instead we passed len, which indicates wrong array size, result in copying random block address into dnode page. Later, once that random block address was accessed by is_checkpointed_data, it can cause NULL pointer dereference. Signed-off-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.