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| author | Nanyong Sun <sunnanyong@huawei.com> | 2024-09-05 23:31:18 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2024-09-09 16:39:14 -0700 |
| commit | 46dcc7c92e63879a49cfbd99949858df0335a122 (patch) | |
| tree | 420fad5ba5967f8ef7228b2978c0b72f79dc19dd /mm/migrate.c | |
| parent | 25e8acbcf19c56fbf0d80615c8f409586aabbf86 (diff) | |
| download | lwn-46dcc7c92e63879a49cfbd99949858df0335a122.tar.gz lwn-46dcc7c92e63879a49cfbd99949858df0335a122.zip | |
mm: migrate: simplify find_mm_struct()
Use find_get_task_by_vpid() to replace the task_struct find logic in
find_mm_struct(), note that this patch move the ptrace_may_access() call
out from rcu_read_lock() scope, this is ok because it actually does not
need it, find_get_task_by_vpid() already get the pid and task safely,
ptrace_may_access() can use the task safely, like what
sched_core_share_pid() similarly do.
Link: https://lkml.kernel.org/r/20240905153118.1205173-1-sunnanyong@huawei.com
Signed-off-by: Nanyong Sun <sunnanyong@huawei.com>
Cc: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/migrate.c')
| -rw-r--r-- | mm/migrate.c | 8 |
1 files changed, 1 insertions, 7 deletions
diff --git a/mm/migrate.c b/mm/migrate.c index 35cc9d35064b..6a68d9923820 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2505,25 +2505,19 @@ static struct mm_struct *find_mm_struct(pid_t pid, nodemask_t *mem_nodes) return current->mm; } - /* Find the mm_struct */ - rcu_read_lock(); - task = find_task_by_vpid(pid); + task = find_get_task_by_vpid(pid); if (!task) { - rcu_read_unlock(); return ERR_PTR(-ESRCH); } - get_task_struct(task); /* * Check if this process has the right to modify the specified * process. Use the regular "ptrace_may_access()" checks. */ if (!ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS)) { - rcu_read_unlock(); mm = ERR_PTR(-EPERM); goto out; } - rcu_read_unlock(); mm = ERR_PTR(security_task_movememory(task)); if (IS_ERR(mm)) |