Messages in this thread Patch in this message | | | Subject | [PATCH] mm: fix protection of mm_struct fields in get_cmdline() | From | Konstantin Khlebnikov <> | Date | Wed, 15 May 2019 11:15:37 +0300 |
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Since commit 88aa7cc688d4 ("mm: introduce arg_lock to protect arg_start| end and env_start|end in mm_struct") related mm fields are protected with separate spinlock and mmap_sem held for read is not enough for protection.
Fixes: 88aa7cc688d4 ("mm: introduce arg_lock to protect arg_start|end and env_start|end in mm_struct") Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> --- mm/util.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/util.c b/mm/util.c index e2e4f8c3fa12..540e7c157cf2 100644 --- a/mm/util.c +++ b/mm/util.c @@ -717,12 +717,12 @@ int get_cmdline(struct task_struct *task, char *buffer, int buflen) if (!mm->arg_end) goto out_mm; /* Shh! No looking before we're done */ - down_read(&mm->mmap_sem); + spin_lock(&mm->arg_lock); arg_start = mm->arg_start; arg_end = mm->arg_end; env_start = mm->env_start; env_end = mm->env_end; - up_read(&mm->mmap_sem); + spin_unlock(&mm->arg_lock); len = arg_end - arg_start;
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