From 9b427edc1d73eee62c152a6edec69cb35525b886 Mon Sep 17 00:00:00 2001 From: Quanyang Wang Date: Tue, 3 Dec 2019 17:01:18 +0800 Subject: [PATCH] yaffs: add strict check when call yaffs_internal_read_super When kernel booting, mount_block_root will be called to judge the filesystem type of root device. Then .mount function in file_system_type structure will do the check operation. But yaffs filesystem has a relaxed examination because as a filesystem for NAND Flash, it doesn't examinate whether the root device is the MTD NAND device. This results that yaffs filesystem will do mount operation even though the root device is a MMC card with a btrfs filesystem, and will crash kernel after mounting failed. The crash log is as below: md: Waiting for all devices to be available before autodetect md: If you don't use raid, use raid=noautodetect md: Autodetecting RAID arrays. md: autorun ... md: ... autorun DONE. yaffs: dev is 187695107 name is "mmcblk0p3" rw yaffs: passed flags "" yaffs: dev is 187695107 name is "mmcblk0p3" rw yaffs: passed flags "" ------------[ cut here ]------------ kernel BUG at fs/yaffs2/yaffs_getblockinfo.h:30! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in: CPU: 3 PID: 1 Comm: swapper/0 Not tainted 5.2.24-yocto-standard+ #250 Hardware name: ZynqMP ZCU102 Rev1.0 (DT) pstate: 80000005 (Nzcv daif -PAN -UAO) pc : yaffs_rd_chunk_tags_nand+0xf0/0x110 lr : yaffs_rd_chunk_tags_nand+0x108/0x110 sp : ffffff801003b770 x29: ffffff801003b770 x28: ffffffc876fe8000 x27: 00000000000c0000 x26: 0000000000000000 x25: 00000000ffffffe1 x24: 0000000000010000 x23: 0000000000000000 x22: ffffff8011228000 x21: 000000000000005f x20: ffffff801003b890 x19: ffffffc876fe8000 x18: ffffffffffffffff x17: 0000000000000000 x16: 0000000000000000 x15: ffffff80112285c8 x14: ffffff801137d228 x13: ffffff801137ce74 x12: ffffff8011246000 x11: 0000000000000000 x10: ffffff801137c000 x9 : 0000000000000000 x8 : 0000000000000007 x7 : 000000000000015c x6 : ffffff801137c490 x5 : 0000000000000000 x4 : 0000000000000000 x3 : 00000000ffffffff x2 : 50c80792e0663400 x1 : 0000000000000000 x0 : 0000000000000037 Call trace: yaffs_rd_chunk_tags_nand+0xf0/0x110 yaffs_summary_read+0x10c/0x2e0 yaffs2_scan_backwards+0x28c/0xf58 yaffs_guts_initialise+0x71c/0x7a0 yaffs_internal_read_super.isra.20+0x4ec/0x838 yaffs2_internal_read_super_mtd+0x2c/0x48 mount_bdev+0x1a4/0x1e0 yaffs2_mount+0x44/0x58 legacy_get_tree+0x34/0x60 vfs_get_tree+0x34/0x120 do_mount+0x708/0x980 ksys_mount+0x9c/0x110 mount_block_root+0x128/0x29c mount_root+0x148/0x17c prepare_namespace+0x178/0x1c0 kernel_init_freeable+0x370/0x390 kernel_init+0x18/0x110 ret_from_fork+0x10/0x1c Code: d65f03c0 f00069c0 b9440400 37f00060 (d4210000) ---[ end trace 68aa0995bdf59f76 ]--- BUG: sleeping function called from invalid context at ./include/linux/percpu-rwsem.h:34 in_atomic(): 1, irqs_disabled(): 128, pid: 1, name: swapper/0 Preemption disabled at: [] debug_exception_enter+0x30/0x40 CPU: 3 PID: 1 Comm: swapper/0 Tainted: G D 5.2.24-yocto-standard+ #250 Hardware name: ZynqMP ZCU102 Rev1.0 (DT) Call trace: dump_backtrace+0x0/0x148 show_stack+0x24/0x30 dump_stack+0x98/0xbc ___might_sleep+0x130/0x188 __might_sleep+0x58/0x90 exit_signals+0x44/0x258 do_exit+0xb4/0xa38 die+0x1bc/0x1e0 bug_handler+0x48/0x98 call_break_hook+0x7c/0xa8 brk_handler+0x28/0x68 do_debug_exception+0xc4/0x188 el1_dbg+0x18/0x8c yaffs_rd_chunk_tags_nand+0xf0/0x110 yaffs_summary_read+0x10c/0x2e0 yaffs2_scan_backwards+0x28c/0xf58 yaffs_guts_initialise+0x71c/0x7a0 yaffs_internal_read_super.isra.20+0x4ec/0x838 yaffs2_internal_read_super_mtd+0x2c/0x48 mount_bdev+0x1a4/0x1e0 yaffs2_mount+0x44/0x58 legacy_get_tree+0x34/0x60 vfs_get_tree+0x34/0x120 do_mount+0x708/0x980 ksys_mount+0x9c/0x110 mount_block_root+0x128/0x29c mount_root+0x148/0x17c prepare_namespace+0x178/0x1c0 kernel_init_freeable+0x370/0x390 kernel_init+0x18/0x110 ret_from_fork+0x10/0x1c note: swapper/0[1] exited with preempt_count 1 Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b SMP: stopping secondary CPUs Kernel Offset: disabled CPU features: 0x0002,20002004 Memory Limit: none ---[ end Kernel panic - not syncing: Attempted to kill init! exitcode=0x0000000b ]--- Use yaffs_get_mtd_device to add strict check. Signed-off-by: Quanyang Wang Signed-off-by: Bruce Ashfield --- fs/yaffs2/yaffs_vfs.c | 7 ++----- 1 file changed, 2 insertions(+), 5 deletions(-) diff --git a/fs/yaffs2/yaffs_vfs.c b/fs/yaffs2/yaffs_vfs.c index 1ddc85b3200da2..d3f89e07401bb2 100644 --- a/fs/yaffs2/yaffs_vfs.c +++ b/fs/yaffs2/yaffs_vfs.c @@ -2960,12 +2960,9 @@ static struct super_block *yaffs_internal_read_super(int yaffs_version, MAJOR(sb->s_dev), MINOR(sb->s_dev), yaffs_devname(sb, devname_buf)); - /* Get the device */ - mtd = get_mtd_device(NULL, MINOR(sb->s_dev)); + + mtd = yaffs_get_mtd_device(sb->s_dev); if (IS_ERR(mtd)) { - yaffs_trace(YAFFS_TRACE_ALWAYS, - "yaffs: MTD device %u either not valid or unavailable", - MINOR(sb->s_dev)); return NULL; }