From 14a958e678cd77cae475b60ca46c0797b1c006a1 Mon Sep 17 00:00:00 2001 From: Filipe David Borba Manana Date: Sun, 12 Jan 2014 02:22:46 +0000 Subject: Btrfs: fix btrfs boot when compiled as built-in After the change titled "Btrfs: add support for inode properties", if btrfs was built-in the kernel (i.e. not as a module), it would cause a kernel panic, as reported recently by Fengguang: [ 2.024722] BUG: unable to handle kernel NULL pointer dereference at (null) [ 2.027814] IP: [] crc32c+0xc/0x6b [ 2.028684] PGD 0 [ 2.028684] Oops: 0000 [#1] SMP [ 2.028684] Modules linked in: [ 2.028684] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.13.0-rc7-04795-ga7b57c2 #1 [ 2.028684] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011 [ 2.028684] task: ffff88000edba100 ti: ffff88000edd6000 task.ti: ffff88000edd6000 [ 2.028684] RIP: 0010:[] [] crc32c+0xc/0x6b [ 2.028684] RSP: 0000:ffff88000edd7e58 EFLAGS: 00010246 [ 2.028684] RAX: 0000000000000000 RBX: ffffffff82295550 RCX: 0000000000000000 [ 2.028684] RDX: 0000000000000011 RSI: ffffffff81efe393 RDI: 00000000fffffffe [ 2.028684] RBP: ffff88000edd7e60 R08: 0000000000000003 R09: 0000000000015d20 [ 2.028684] R10: ffffffff81ef225e R11: ffffffff811b0222 R12: ffffffffffffffff [ 2.028684] R13: 0000000000000239 R14: 0000000000000000 R15: 0000000000000000 [ 2.028684] FS: 0000000000000000(0000) GS:ffff88000fa00000(0000) knlGS:0000000000000000 [ 2.028684] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [ 2.028684] CR2: 0000000000000000 CR3: 000000000220c000 CR4: 00000000000006f0 [ 2.028684] Stack: [ 2.028684] ffffffff82295550 ffff88000edd7e80 ffffffff8238af62 ffffffff8238ac05 [ 2.028684] 0000000000000000 ffff88000edd7e98 ffffffff8238ac0f ffffffff8238ac05 [ 2.028684] ffff88000edd7f08 ffffffff810002ba ffff88000edd7f00 ffffffff810e2404 [ 2.028684] Call Trace: [ 2.028684] [] btrfs_props_init+0x4f/0x96 [ 2.028684] [] ? ftrace_define_fields_btrfs_space_reservation+0x145/0x145 [ 2.028684] [] init_btrfs_fs+0xa/0xf0 [ 2.028684] [] ? ftrace_define_fields_btrfs_space_reservation+0x145/0x145 [ 2.028684] [] do_one_initcall+0xa4/0x13a [ 2.028684] [] ? parse_args+0x25f/0x33d [ 2.028684] [] kernel_init_freeable+0x1aa/0x230 [ 2.028684] [] ? do_early_param+0x88/0x88 [ 2.028684] [] ? rest_init+0x89/0x89 [ 2.028684] [] kernel_init+0xe/0x109 The issue here is that the initialization function of btrfs (super.c:init_btrfs_fs) started using crc32c (from lib/libcrc32c.c). But when it needs to call crc32c (as part of the properties initialization routine), the libcrc32c is not yet initialized, so crc32c derreferenced a NULL pointer (lib/libcrc32c.c:tfm), causing the kernel panic on boot. The approach to fix this is to use crypto component directly to use its crc32c (which is basically what lib/libcrc32c.c is, a wrapper around crypto). This is what ext4 is doing as well, it uses crypto directly to get crc32c functionality. Verified this works both when btrfs is built-in and when it's loadable kernel module. Signed-off-by: Filipe David Borba Manana Signed-off-by: Josef Bacik Signed-off-by: Chris Mason --- fs/btrfs/Makefile | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'fs/btrfs/Makefile') diff --git a/fs/btrfs/Makefile b/fs/btrfs/Makefile index af7f000e905c..f341a98031d2 100644 --- a/fs/btrfs/Makefile +++ b/fs/btrfs/Makefile @@ -9,7 +9,7 @@ btrfs-y += super.o ctree.o extent-tree.o print-tree.o root-tree.o dir-item.o \ export.o tree-log.o free-space-cache.o zlib.o lzo.o \ compression.o delayed-ref.o relocation.o delayed-inode.o scrub.o \ reada.o backref.o ulist.o qgroup.o send.o dev-replace.o raid56.o \ - uuid-tree.o props.o + uuid-tree.o props.o hash.o btrfs-$(CONFIG_BTRFS_FS_POSIX_ACL) += acl.o btrfs-$(CONFIG_BTRFS_FS_CHECK_INTEGRITY) += check-integrity.o -- cgit v1.2.3-73-gaa49b