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cfq-iosched: fix sysfs oops when attempting to read unconfigured weights
If none of the devices in the system are using CFQ, then attempting to
read:
/sys/fs/cgroup/blkio/blkio.leaf_weight
will results in a NULL dereference. Check for a valid cfq_group_data
struct before attempting to dereference it.
Reported-by: Andrey Wagin <avagin@gmail.com>
Fixes: e48453c3
("block, cgroup: implement policy-specific per-blkcg data")
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
parent
4ceab71b9d
commit
9470e4a693
1 changed files with 12 additions and 2 deletions
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@ -1714,16 +1714,26 @@ static int cfqg_print_leaf_weight_device(struct seq_file *sf, void *v)
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static int cfq_print_weight(struct seq_file *sf, void *v)
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{
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struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
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struct cfq_group_data *cgd = blkcg_to_cfqgd(blkcg);
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unsigned int val = 0;
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seq_printf(sf, "%u\n", blkcg_to_cfqgd(blkcg)->weight);
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if (cgd)
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val = cgd->weight;
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seq_printf(sf, "%u\n", val);
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return 0;
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}
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static int cfq_print_leaf_weight(struct seq_file *sf, void *v)
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{
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struct blkcg *blkcg = css_to_blkcg(seq_css(sf));
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struct cfq_group_data *cgd = blkcg_to_cfqgd(blkcg);
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unsigned int val = 0;
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seq_printf(sf, "%u\n", blkcg_to_cfqgd(blkcg)->leaf_weight);
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if (cgd)
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val = cgd->leaf_weight;
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seq_printf(sf, "%u\n", val);
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return 0;
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}
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