| Message ID | 20240227091148.178435-6-libaokun1@huawei.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | ext4: avoid sysfs variables overflow causing BUG_ON/SOOB | expand |
On Tue 27-02-24 17:11:44, Baokun Li wrote: > The s_mb_best_avail_max_trim_order is of type unsigned int, and has a > range of values well beyond the normal use of the mb_order. Although the > mballoc code is careful enough that large numbers don't matter there, but > this can mislead the sysadmin into thinking that it's normal to set such > values. Hence add a new attr_id attr_mb_order with values in the range > [0, 64] to avoid storing garbage values and make us more resilient to > surprises in the future. > > Suggested-by: Jan Kara <jack@suse.cz> > Signed-off-by: Baokun Li <libaokun1@huawei.com> Looks good. Feel free to add: Reviewed-by: Jan Kara <jack@suse.cz> Honza > --- > fs/ext4/sysfs.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c > index ddd71673176c..8e0473169458 100644 > --- a/fs/ext4/sysfs.c > +++ b/fs/ext4/sysfs.c > @@ -30,6 +30,7 @@ typedef enum { > attr_first_error_time, > attr_last_error_time, > attr_clusters_in_group, > + attr_mb_order, > attr_feature, > attr_pointer_ui, > attr_pointer_ul, > @@ -210,6 +211,8 @@ EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead, > ext4_sb_info, s_inode_readahead_blks); > EXT4_ATTR_OFFSET(mb_group_prealloc, 0644, clusters_in_group, > ext4_sb_info, s_mb_group_prealloc); > +EXT4_ATTR_OFFSET(mb_best_avail_max_trim_order, 0644, mb_order, > + ext4_sb_info, s_mb_best_avail_max_trim_order); > EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal); > EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats); > EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan); > @@ -225,7 +228,6 @@ EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.int > EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst); > EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval); > EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst); > -EXT4_RW_ATTR_SBI_UI(mb_best_avail_max_trim_order, s_mb_best_avail_max_trim_order); > #ifdef CONFIG_EXT4_DEBUG > EXT4_RW_ATTR_SBI_UL(simulate_fail, s_simulate_fail); > #endif > @@ -379,6 +381,7 @@ static ssize_t ext4_generic_attr_show(struct ext4_attr *a, > switch (a->attr_id) { > case attr_inode_readahead: > case attr_clusters_in_group: > + case attr_mb_order: > case attr_pointer_ui: > if (a->attr_ptr == ptr_ext4_super_block_offset) > return sysfs_emit(buf, "%u\n", le32_to_cpup(ptr)); > @@ -458,6 +461,14 @@ static ssize_t ext4_generic_attr_store(struct ext4_attr *a, > else > *((unsigned int *) ptr) = t; > return len; > + case attr_mb_order: > + ret = kstrtouint(skip_spaces(buf), 0, &t); > + if (ret) > + return ret; > + if (t > 64) > + return -EINVAL; > + *((unsigned int *) ptr) = t; > + return len; > case attr_clusters_in_group: > ret = kstrtouint(skip_spaces(buf), 0, &t); > if (ret) > -- > 2.31.1 >
diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c index ddd71673176c..8e0473169458 100644 --- a/fs/ext4/sysfs.c +++ b/fs/ext4/sysfs.c @@ -30,6 +30,7 @@ typedef enum { attr_first_error_time, attr_last_error_time, attr_clusters_in_group, + attr_mb_order, attr_feature, attr_pointer_ui, attr_pointer_ul, @@ -210,6 +211,8 @@ EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead, ext4_sb_info, s_inode_readahead_blks); EXT4_ATTR_OFFSET(mb_group_prealloc, 0644, clusters_in_group, ext4_sb_info, s_mb_group_prealloc); +EXT4_ATTR_OFFSET(mb_best_avail_max_trim_order, 0644, mb_order, + ext4_sb_info, s_mb_best_avail_max_trim_order); EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal); EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats); EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan); @@ -225,7 +228,6 @@ EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.int EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst); EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval); EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst); -EXT4_RW_ATTR_SBI_UI(mb_best_avail_max_trim_order, s_mb_best_avail_max_trim_order); #ifdef CONFIG_EXT4_DEBUG EXT4_RW_ATTR_SBI_UL(simulate_fail, s_simulate_fail); #endif @@ -379,6 +381,7 @@ static ssize_t ext4_generic_attr_show(struct ext4_attr *a, switch (a->attr_id) { case attr_inode_readahead: case attr_clusters_in_group: + case attr_mb_order: case attr_pointer_ui: if (a->attr_ptr == ptr_ext4_super_block_offset) return sysfs_emit(buf, "%u\n", le32_to_cpup(ptr)); @@ -458,6 +461,14 @@ static ssize_t ext4_generic_attr_store(struct ext4_attr *a, else *((unsigned int *) ptr) = t; return len; + case attr_mb_order: + ret = kstrtouint(skip_spaces(buf), 0, &t); + if (ret) + return ret; + if (t > 64) + return -EINVAL; + *((unsigned int *) ptr) = t; + return len; case attr_clusters_in_group: ret = kstrtouint(skip_spaces(buf), 0, &t); if (ret)
The s_mb_best_avail_max_trim_order is of type unsigned int, and has a range of values well beyond the normal use of the mb_order. Although the mballoc code is careful enough that large numbers don't matter there, but this can mislead the sysadmin into thinking that it's normal to set such values. Hence add a new attr_id attr_mb_order with values in the range [0, 64] to avoid storing garbage values and make us more resilient to surprises in the future. Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Baokun Li <libaokun1@huawei.com> --- fs/ext4/sysfs.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)