"Sasha" == Sasha Levin sashal@kernel.org writes:
My fault. I was just pointing out that 'special' was spelled wrong in the messages, you had: speical.
John
Sasha> I'm sorry, I couldn't parse the mail below.
Sasha> On Wed, Jun 01, 2022 at 05:36:15PM -0400, John Stoffel wrote:
> "Sasha" == Sasha Levin sashal@kernel.org writes:
Sasha> From: Heming Zhao heming.zhao@suse.com Sasha> [ Upstream commit e68cb83a57a458b01c9739e2ad9cb70b04d1e6d2 ]
Sasha> If bitmap area contains invalid data, kernel will crash then mdadm Sasha> triggers "Segmentation fault". Sasha> This is cluster-md speical bug. In non-clustered env, mdadm will
special
All the commit messages need to be fixed from what I see.
Sasha> handle broken metadata case. In clustered array, only kernel space Sasha> handles bitmap slot info. But even this bug only happened in clustered Sasha> env, current sanity check is wrong, the code should be changed.
Sasha> How to trigger: (faulty injection)
Sasha> dd if=/dev/zero bs=1M count=1 oflag=direct of=/dev/sda Sasha> dd if=/dev/zero bs=1M count=1 oflag=direct of=/dev/sdb Sasha> mdadm -C /dev/md0 -b clustered -e 1.2 -n 2 -l mirror /dev/sda /dev/sdb Sasha> mdadm -Ss Sasha> echo aaa > magic.txt Sasha> == below modifying slot 2 bitmap data == Sasha> dd if=magic.txt of=/dev/sda seek=16384 bs=1 count=3 <== destroy magic Sasha> dd if=/dev/zero of=/dev/sda seek=16436 bs=1 count=4 <== ZERO chunksize Sasha> mdadm -A /dev/md0 /dev/sda /dev/sdb Sasha> == kernel crashes. mdadm outputs "Segmentation fault" ==
Sasha> Reason of kernel crash:
Sasha> In md_bitmap_read_sb (called by md_bitmap_create), bad bitmap magic didn't Sasha> block chunksize assignment, and zero value made DIV_ROUND_UP_SECTOR_T() Sasha> trigger "divide error".
Sasha> Crash log:
Sasha> kernel: md: md0 stopped. Sasha> kernel: md/raid1:md0: not clean -- starting background reconstruction Sasha> kernel: md/raid1:md0: active with 2 out of 2 mirrors Sasha> kernel: dlm: ... ... Sasha> kernel: md-cluster: Joined cluster 44810aba-38bb-e6b8-daca-bc97a0b254aa slot 1 Sasha> kernel: md0: invalid bitmap file superblock: bad magic Sasha> kernel: md_bitmap_copy_from_slot can't get bitmap from slot 2 Sasha> kernel: md-cluster: Could not gather bitmaps from slot 2 Sasha> kernel: divide error: 0000 [#1] SMP NOPTI Sasha> kernel: CPU: 0 PID: 1603 Comm: mdadm Not tainted 5.14.6-1-default Sasha> kernel: Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) Sasha> kernel: RIP: 0010:md_bitmap_create+0x1d1/0x850 [md_mod] Sasha> kernel: RSP: 0018:ffffc22ac0843ba0 EFLAGS: 00010246 Sasha> kernel: ... ... Sasha> kernel: Call Trace: Sasha> kernel: ? dlm_lock_sync+0xd0/0xd0 [md_cluster 77fe..7a0] Sasha> kernel: md_bitmap_copy_from_slot+0x2c/0x290 [md_mod 24ea..d3a] Sasha> kernel: load_bitmaps+0xec/0x210 [md_cluster 77fe..7a0] Sasha> kernel: md_bitmap_load+0x81/0x1e0 [md_mod 24ea..d3a] Sasha> kernel: do_md_run+0x30/0x100 [md_mod 24ea..d3a] Sasha> kernel: md_ioctl+0x1290/0x15a0 [md_mod 24ea....d3a] Sasha> kernel: ? mddev_unlock+0xaa/0x130 [md_mod 24ea..d3a] Sasha> kernel: ? blkdev_ioctl+0xb1/0x2b0 Sasha> kernel: block_ioctl+0x3b/0x40 Sasha> kernel: __x64_sys_ioctl+0x7f/0xb0 Sasha> kernel: do_syscall_64+0x59/0x80 Sasha> kernel: ? exit_to_user_mode_prepare+0x1ab/0x230 Sasha> kernel: ? syscall_exit_to_user_mode+0x18/0x40 Sasha> kernel: ? do_syscall_64+0x69/0x80 Sasha> kernel: entry_SYSCALL_64_after_hwframe+0x44/0xae Sasha> kernel: RIP: 0033:0x7f4a15fa722b Sasha> kernel: ... ... Sasha> kernel: ---[ end trace 8afa7612f559c868 ]--- Sasha> kernel: RIP: 0010:md_bitmap_create+0x1d1/0x850 [md_mod]
Sasha> Reported-by: kernel test robot lkp@intel.com Sasha> Reported-by: Dan Carpenter dan.carpenter@oracle.com Sasha> Acked-by: Guoqing Jiang guoqing.jiang@linux.dev Sasha> Signed-off-by: Heming Zhao heming.zhao@suse.com Sasha> Signed-off-by: Song Liu song@kernel.org Sasha> Signed-off-by: Sasha Levin sashal@kernel.org Sasha> --- Sasha> drivers/md/md-bitmap.c | 44 ++++++++++++++++++++++-------------------- Sasha> 1 file changed, 23 insertions(+), 21 deletions(-)
Sasha> diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c Sasha> index d7eef5292ae2..a95e20c3d0d4 100644 Sasha> --- a/drivers/md/md-bitmap.c Sasha> +++ b/drivers/md/md-bitmap.c Sasha> @@ -642,14 +642,6 @@ static int md_bitmap_read_sb(struct bitmap *bitmap) Sasha> daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ; Sasha> write_behind = le32_to_cpu(sb->write_behind); Sasha> sectors_reserved = le32_to_cpu(sb->sectors_reserved); Sasha> - /* Setup nodes/clustername only if bitmap version is Sasha> - * cluster-compatible Sasha> - */ Sasha> - if (sb->version == cpu_to_le32(BITMAP_MAJOR_CLUSTERED)) { Sasha> - nodes = le32_to_cpu(sb->nodes); Sasha> - strlcpy(bitmap->mddev->bitmap_info.cluster_name, Sasha> - sb->cluster_name, 64); Sasha> - }
Sasha> /* verify that the bitmap-specific fields are valid */ Sasha> if (sb->magic != cpu_to_le32(BITMAP_MAGIC)) Sasha> @@ -671,6 +663,16 @@ static int md_bitmap_read_sb(struct bitmap *bitmap) Sasha> goto out; Sasha> }
Sasha> + /* Sasha> + * Setup nodes/clustername only if bitmap version is Sasha> + * cluster-compatible Sasha> + */ Sasha> + if (sb->version == cpu_to_le32(BITMAP_MAJOR_CLUSTERED)) { Sasha> + nodes = le32_to_cpu(sb->nodes); Sasha> + strlcpy(bitmap->mddev->bitmap_info.cluster_name, Sasha> + sb->cluster_name, 64); Sasha> + } Sasha> + Sasha> /* keep the array size field of the bitmap superblock up to date */ sb-> sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
Sasha> @@ -703,9 +705,9 @@ static int md_bitmap_read_sb(struct bitmap *bitmap)
Sasha> out: Sasha> kunmap_atomic(sb); Sasha> - /* Assigning chunksize is required for "re_read" */ Sasha> - bitmap->mddev->bitmap_info.chunksize = chunksize; Sasha> if (err == 0 && nodes && (bitmap->cluster_slot < 0)) { Sasha> + /* Assigning chunksize is required for "re_read" */ Sasha> + bitmap->mddev->bitmap_info.chunksize = chunksize; Sasha> err = md_setup_cluster(bitmap->mddev, nodes); Sasha> if (err) { Sasha> pr_warn("%s: Could not setup cluster service (%d)\n", Sasha> @@ -716,18 +718,18 @@ static int md_bitmap_read_sb(struct bitmap *bitmap) Sasha> goto re_read; Sasha> }
Sasha> - Sasha> out_no_sb: Sasha> - if (test_bit(BITMAP_STALE, &bitmap->flags)) Sasha> - bitmap->events_cleared = bitmap->mddev->events; Sasha> - bitmap->mddev->bitmap_info.chunksize = chunksize; Sasha> - bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep; Sasha> - bitmap->mddev->bitmap_info.max_write_behind = write_behind; Sasha> - bitmap->mddev->bitmap_info.nodes = nodes; Sasha> - if (bitmap->mddev->bitmap_info.space == 0 || Sasha> - bitmap->mddev->bitmap_info.space > sectors_reserved) Sasha> - bitmap->mddev->bitmap_info.space = sectors_reserved; Sasha> - if (err) { Sasha> + if (err == 0) { Sasha> + if (test_bit(BITMAP_STALE, &bitmap->flags)) Sasha> + bitmap->events_cleared = bitmap->mddev->events; Sasha> + bitmap->mddev->bitmap_info.chunksize = chunksize; Sasha> + bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep; Sasha> + bitmap->mddev->bitmap_info.max_write_behind = write_behind; Sasha> + bitmap->mddev->bitmap_info.nodes = nodes; Sasha> + if (bitmap->mddev->bitmap_info.space == 0 || Sasha> + bitmap->mddev->bitmap_info.space > sectors_reserved) Sasha> + bitmap->mddev->bitmap_info.space = sectors_reserved; Sasha> + } else { Sasha> md_bitmap_print_sb(bitmap); Sasha> if (bitmap->cluster_slot < 0) Sasha> md_cluster_stop(bitmap->mddev); Sasha> -- Sasha> 2.35.1
Sasha> -- Sasha> Thanks, Sasha> Sasha