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| author | Jann Horn <jannh@google.com> | 2022-04-05 18:39:31 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-06-25 11:46:37 +0200 |
| commit | cf8136b351692783036bc4eb0df85ebaf453d8b5 (patch) | |
| tree | 15a49f0c5d98cf40db76e2576df74dae3481e3bd /drivers/char | |
| parent | 04d681d81b7dfbfc5f33094914de96e2e047f22f (diff) | |
| download | linux-stable-cf8136b351692783036bc4eb0df85ebaf453d8b5.tar.gz linux-stable-cf8136b351692783036bc4eb0df85ebaf453d8b5.tar.bz2 linux-stable-cf8136b351692783036bc4eb0df85ebaf453d8b5.zip | |
random: check for signal_pending() outside of need_resched() check
commit 1448769c9cdb69ad65287f4f7ab58bc5f2f5d7ba upstream.
signal_pending() checks TIF_NOTIFY_SIGNAL and TIF_SIGPENDING, which
signal that the task should bail out of the syscall when possible. This
is a separate concept from need_resched(), which checks
TIF_NEED_RESCHED, signaling that the task should preempt.
In particular, with the current code, the signal_pending() bailout
probably won't work reliably.
Change this to look like other functions that read lots of data, such as
read_zero().
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Jann Horn <jannh@google.com>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/random.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index cae0a6e5a9e9..a2e80bf9060f 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -549,13 +549,13 @@ static ssize_t get_random_bytes_user(void __user *buf, size_t nbytes) } do { - if (large_request && need_resched()) { + if (large_request) { if (signal_pending(current)) { if (!ret) ret = -ERESTARTSYS; break; } - schedule(); + cond_resched(); } chacha20_block(chacha_state, output); |