On Sun, Dec 15, 2019 at 7:30 AM Theodore Y. Ts'o <tytso@xxxxxxx> wrote: > > On Sat, Dec 14, 2019 at 05:27:00PM -0800, syzbot wrote: > > syzbot has bisected this bug to: > > > > commit 8835cae5f2abd7f7a3143afe357f416aff5517a4 > > Author: Chris Lapa <chris@xxxxxxxxxxx> > > Date: Wed Jan 11 01:44:47 2017 +0000 > > > > power: supply: bq27xxx: adds specific support for bq27520-g4 revision. > > This is pretty clearly nonsense. Agree. FTR, it seems that bisection was first diverged by this kernel bug: testing commit 8835cae5f2abd7f7a3143afe357f416aff5517a4 with gcc (GCC) 5.5.0 run #0: crashed: WARNING in batadv_mcast_mla_update on top of this non-deterministic kernel build bug kicked in to prevent detection of "culprit does not affect build": culprit signature: 2aca06cd9a4175f124f866fe66467cfa96c0bf2a parent signature: 8a8dd9ca5726f129b6d36eb6e1f3b78cc7c18b31 > However let's try this fix: > > #syz test: https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git master > > From 9c962de70a52e0b24fba00ee7b8707964d3d1e37 Mon Sep 17 00:00:00 2001 > From: Theodore Ts'o <tytso@xxxxxxx> > Date: Sun, 15 Dec 2019 01:09:03 -0500 > Subject: [PATCH] ext4: validate the debug_want_extra_isize mount option at parse time > > Instead of setting s_want_extra_size and then making sure that it is a > valid value afterwards, validate the field before we set it. This > avoids races and other problems when remounting the file system. > > Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> > Reported-by: syzbot+4a39a025912b265cacef@xxxxxxxxxxxxxxxxxxxxxxxxx > --- > fs/ext4/super.c | 143 +++++++++++++++++++++++------------------------- > 1 file changed, 69 insertions(+), 74 deletions(-) > > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > index b205112ca051..46b6d5b150ac 100644 > --- a/fs/ext4/super.c > +++ b/fs/ext4/super.c > @@ -1886,6 +1886,13 @@ static int handle_mount_opt(struct super_block *sb, char *opt, int token, > } > sbi->s_commit_interval = HZ * arg; > } else if (token == Opt_debug_want_extra_isize) { > + if ((arg & 1) || > + (arg < 4) || > + (arg > (sbi->s_inode_size - EXT4_GOOD_OLD_INODE_SIZE))) { > + ext4_msg(sb, KERN_ERR, > + "Invalid want_extra_isize %d", arg); > + return -1; > + } > sbi->s_want_extra_isize = arg; > } else if (token == Opt_max_batch_time) { > sbi->s_max_batch_time = arg; > @@ -3540,40 +3547,6 @@ int ext4_calculate_overhead(struct super_block *sb) > return 0; > } > > -static void ext4_clamp_want_extra_isize(struct super_block *sb) > -{ > - struct ext4_sb_info *sbi = EXT4_SB(sb); > - struct ext4_super_block *es = sbi->s_es; > - unsigned def_extra_isize = sizeof(struct ext4_inode) - > - EXT4_GOOD_OLD_INODE_SIZE; > - > - if (sbi->s_inode_size == EXT4_GOOD_OLD_INODE_SIZE) { > - sbi->s_want_extra_isize = 0; > - return; > - } > - if (sbi->s_want_extra_isize < 4) { > - sbi->s_want_extra_isize = def_extra_isize; > - if (ext4_has_feature_extra_isize(sb)) { > - if (sbi->s_want_extra_isize < > - le16_to_cpu(es->s_want_extra_isize)) > - sbi->s_want_extra_isize = > - le16_to_cpu(es->s_want_extra_isize); > - if (sbi->s_want_extra_isize < > - le16_to_cpu(es->s_min_extra_isize)) > - sbi->s_want_extra_isize = > - le16_to_cpu(es->s_min_extra_isize); > - } > - } > - /* Check if enough inode space is available */ > - if ((sbi->s_want_extra_isize > sbi->s_inode_size) || > - (EXT4_GOOD_OLD_INODE_SIZE + sbi->s_want_extra_isize > > - sbi->s_inode_size)) { > - sbi->s_want_extra_isize = def_extra_isize; > - ext4_msg(sb, KERN_INFO, > - "required extra inode space not available"); > - } > -} > - > static void ext4_set_resv_clusters(struct super_block *sb) > { > ext4_fsblk_t resv_clusters; > @@ -3781,6 +3754,68 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) > */ > sbi->s_li_wait_mult = EXT4_DEF_LI_WAIT_MULT; > > + if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) { > + sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE; > + sbi->s_first_ino = EXT4_GOOD_OLD_FIRST_INO; > + } else { > + sbi->s_inode_size = le16_to_cpu(es->s_inode_size); > + sbi->s_first_ino = le32_to_cpu(es->s_first_ino); > + if (sbi->s_first_ino < EXT4_GOOD_OLD_FIRST_INO) { > + ext4_msg(sb, KERN_ERR, "invalid first ino: %u", > + sbi->s_first_ino); > + goto failed_mount; > + } > + if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) || > + (!is_power_of_2(sbi->s_inode_size)) || > + (sbi->s_inode_size > blocksize)) { > + ext4_msg(sb, KERN_ERR, > + "unsupported inode size: %d", > + sbi->s_inode_size); > + goto failed_mount; > + } > + /* > + * i_atime_extra is the last extra field available for > + * [acm]times in struct ext4_inode. Checking for that > + * field should suffice to ensure we have extra space > + * for all three. > + */ > + if (sbi->s_inode_size >= offsetof(struct ext4_inode, i_atime_extra) + > + sizeof(((struct ext4_inode *)0)->i_atime_extra)) { > + sb->s_time_gran = 1; > + sb->s_time_max = EXT4_EXTRA_TIMESTAMP_MAX; > + } else { > + sb->s_time_gran = NSEC_PER_SEC; > + sb->s_time_max = EXT4_NON_EXTRA_TIMESTAMP_MAX; > + } > + sb->s_time_min = EXT4_TIMESTAMP_MIN; > + } > + if (sbi->s_inode_size > EXT4_GOOD_OLD_INODE_SIZE) { > + sbi->s_want_extra_isize = sizeof(struct ext4_inode) - > + EXT4_GOOD_OLD_INODE_SIZE; > + if (ext4_has_feature_extra_isize(sb)) { > + unsigned v, max = (sbi->s_inode_size - > + EXT4_GOOD_OLD_INODE_SIZE); > + > + v = le16_to_cpu(es->s_want_extra_isize); > + if (v > max) { > + ext4_msg(sb, KERN_ERR, > + "bad s_want_extra_isize: %d", v); > + goto failed_mount; > + } > + if (sbi->s_want_extra_isize < v) > + sbi->s_want_extra_isize = v; > + > + v = le16_to_cpu(es->s_min_extra_isize); > + if (v > max) { > + ext4_msg(sb, KERN_ERR, > + "bad s_min_extra_isize: %d", v); > + goto failed_mount; > + } > + if (sbi->s_want_extra_isize < v) > + sbi->s_want_extra_isize = v; > + } > + } > + > if (sbi->s_es->s_mount_opts[0]) { > char *s_mount_opts = kstrndup(sbi->s_es->s_mount_opts, > sizeof(sbi->s_es->s_mount_opts), > @@ -4019,42 +4054,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) > has_huge_files); > sb->s_maxbytes = ext4_max_size(sb->s_blocksize_bits, has_huge_files); > > - if (le32_to_cpu(es->s_rev_level) == EXT4_GOOD_OLD_REV) { > - sbi->s_inode_size = EXT4_GOOD_OLD_INODE_SIZE; > - sbi->s_first_ino = EXT4_GOOD_OLD_FIRST_INO; > - } else { > - sbi->s_inode_size = le16_to_cpu(es->s_inode_size); > - sbi->s_first_ino = le32_to_cpu(es->s_first_ino); > - if (sbi->s_first_ino < EXT4_GOOD_OLD_FIRST_INO) { > - ext4_msg(sb, KERN_ERR, "invalid first ino: %u", > - sbi->s_first_ino); > - goto failed_mount; > - } > - if ((sbi->s_inode_size < EXT4_GOOD_OLD_INODE_SIZE) || > - (!is_power_of_2(sbi->s_inode_size)) || > - (sbi->s_inode_size > blocksize)) { > - ext4_msg(sb, KERN_ERR, > - "unsupported inode size: %d", > - sbi->s_inode_size); > - goto failed_mount; > - } > - /* > - * i_atime_extra is the last extra field available for [acm]times in > - * struct ext4_inode. Checking for that field should suffice to ensure > - * we have extra space for all three. > - */ > - if (sbi->s_inode_size >= offsetof(struct ext4_inode, i_atime_extra) + > - sizeof(((struct ext4_inode *)0)->i_atime_extra)) { > - sb->s_time_gran = 1; > - sb->s_time_max = EXT4_EXTRA_TIMESTAMP_MAX; > - } else { > - sb->s_time_gran = NSEC_PER_SEC; > - sb->s_time_max = EXT4_NON_EXTRA_TIMESTAMP_MAX; > - } > - > - sb->s_time_min = EXT4_TIMESTAMP_MIN; > - } > - > sbi->s_desc_size = le16_to_cpu(es->s_desc_size); > if (ext4_has_feature_64bit(sb)) { > if (sbi->s_desc_size < EXT4_MIN_DESC_SIZE_64BIT || > @@ -4503,8 +4502,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) > } else if (ret) > goto failed_mount4a; > > - ext4_clamp_want_extra_isize(sb); > - > ext4_set_resv_clusters(sb); > > err = ext4_setup_system_zone(sb); > @@ -5292,8 +5289,6 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data) > goto restore_opts; > } > > - ext4_clamp_want_extra_isize(sb); > - > if ((old_opts.s_mount_opt & EXT4_MOUNT_JOURNAL_CHECKSUM) ^ > test_opt(sb, JOURNAL_CHECKSUM)) { > ext4_msg(sb, KERN_ERR, "changing journal_checksum " > -- > 2.24.1 > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/20191215063020.GA11512%40mit.edu.
