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mm: use pidfd_get_task()

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Instead of duplicating the same code in two places use the newly added
pidfd_get_task() helper. This fixes an (unimportant for now) bug where
PIDTYPE_PID is used whereas PIDTYPE_TGID should have been used.

Link: https://lore.kernel.org/r/20211004125050.1153693-3-christian.brauner@ubuntu.com
Link: https://lore.kernel.org/r/20211011133245.1703103-3-brauner@kernel.org
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Matthew Bobrowski <repnop@google.com>
Cc: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Minchan Kim <minchan@kernel.org>
Reviewed-by: Matthew Bobrowski <repnop@google.com>
Acked-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
This commit is contained in:
Christian Brauner 2021-10-11 15:32:45 +02:00
parent e9bdcdbf69
commit ee9955d61a
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
2 changed files with 6 additions and 24 deletions
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15
mm/madvise.c
View File

@ -1235,7 +1235,6 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec,
struct iovec iovstack[UIO_FASTIOV], iovec;
struct iovec *iov = iovstack;
struct iov_iter iter;
struct pid *pid;
struct task_struct *task;
struct mm_struct *mm;
size_t total_len;
@ -1250,18 +1249,12 @@ SYSCALL_DEFINE5(process_madvise, int, pidfd, const struct iovec __user *, vec,
if (ret < 0)
goto out;
pid = pidfd_get_pid(pidfd, &f_flags);
if (IS_ERR(pid)) {
ret = PTR_ERR(pid);
task = pidfd_get_task(pidfd, &f_flags);
if (IS_ERR(task)) {
ret = PTR_ERR(task);
goto free_iov;
}
task = get_pid_task(pid, PIDTYPE_PID);
if (!task) {
ret = -ESRCH;
goto put_pid;
}
if (!process_madvise_behavior_valid(behavior)) {
ret = -EINVAL;
goto release_task;
@ -1301,8 +1294,6 @@ release_mm:
mmput(mm);
release_task:
put_task_struct(task);
put_pid:
put_pid(pid);
free_iov:
kfree(iov);
out:

15
mm/oom_kill.c
View File

@ -1151,21 +1151,14 @@ SYSCALL_DEFINE2(process_mrelease, int, pidfd, unsigned int, flags)
struct task_struct *p;
unsigned int f_flags;
bool reap = true;
struct pid *pid;
long ret = 0;
if (flags)
return -EINVAL;
pid = pidfd_get_pid(pidfd, &f_flags);
if (IS_ERR(pid))
return PTR_ERR(pid);
task = get_pid_task(pid, PIDTYPE_TGID);
if (!task) {
ret = -ESRCH;
goto put_pid;
}
task = pidfd_get_task(pidfd, &f_flags);
if (IS_ERR(task))
return PTR_ERR(task);
/*
* Make sure to choose a thread which still has a reference to mm
@ -1204,8 +1197,6 @@ drop_mm:
mmdrop(mm);
put_task:
put_task_struct(task);
put_pid:
put_pid(pid);
return ret;
#else
return -ENOSYS;