Messages in this thread | | | Date | Wed, 30 May 2007 22:45:47 +0900 | From | Tejun Heo <> | Subject | Re: [PATCH 4/6] sysfs: use sysfs_lock to protect the sysfs_dirent tree |
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Cornelia Huck wrote: > On Tue, 29 May 2007 01:36:27 +0900, > Tejun Heo <htejun@gmail.com> wrote: > >> @@ -795,6 +822,8 @@ static int sysfs_readdir(struct file * f >> i++; >> /* fallthrough */ >> default: >> + spin_lock(&sysfs_lock); >> + >> pos = &parent_sd->s_children; >> while (*pos != cursor) >> pos = &(*pos)->s_sibling; >> @@ -827,6 +856,8 @@ static int sysfs_readdir(struct file * f >> /* put cursor back in */ >> cursor->s_sibling = *pos; >> *pos = cursor; >> + >> + spin_unlock(&sysfs_lock); >> } >> return 0; >> } > > Here's the cause of the "sleeping function called" I saw. filldir() is > called under sysfs_lock, but calls copy_to_user()... This means you > can't use sysfs_lock for protection here.
Ouch, right. I think we can get away with a temp buffer there. Thanks.
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