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From: Jens Axboe <[email protected]>
To: [email protected]
Cc: [email protected], [email protected],
	[email protected], [email protected], [email protected],
	Jens Axboe <[email protected]>
Subject: [PATCH 3/7] kernel: stop masking signals in create_io_thread()
Date: Fri, 26 Mar 2021 09:51:17 -0600	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

This is racy - move the blocking into when the task is created and
we're marking it as PF_IO_WORKER anyway. The IO threads are now
prepared to handle signals like SIGSTOP as well, so clear that from
the mask to allow proper stopping of IO threads.

Reported-by: Oleg Nesterov <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
---
 kernel/fork.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/kernel/fork.c b/kernel/fork.c
index d3171e8e88e5..ddaa15227071 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -1940,8 +1940,14 @@ static __latent_entropy struct task_struct *copy_process(
 	p = dup_task_struct(current, node);
 	if (!p)
 		goto fork_out;
-	if (args->io_thread)
+	if (args->io_thread) {
+		/*
+		 * Mark us an IO worker, and block any signal that isn't
+		 * fatal or STOP
+		 */
 		p->flags |= PF_IO_WORKER;
+		siginitsetinv(&p->blocked, sigmask(SIGKILL)|sigmask(SIGSTOP));
+	}
 
 	/*
 	 * This _must_ happen before we call free_task(), i.e. before we jump
@@ -2430,14 +2436,8 @@ struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node)
 		.stack_size	= (unsigned long)arg,
 		.io_thread	= 1,
 	};
-	struct task_struct *tsk;
 
-	tsk = copy_process(NULL, 0, node, &args);
-	if (!IS_ERR(tsk)) {
-		sigfillset(&tsk->blocked);
-		sigdelsetmask(&tsk->blocked, sigmask(SIGKILL));
-	}
-	return tsk;
+	return copy_process(NULL, 0, node, &args);
 }
 
 /*
-- 
2.31.0


  parent reply	other threads:[~2021-03-26 15:52 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-26 15:51 [PATCHSET v2 0/7] Allow signals for IO threads Jens Axboe
2021-03-26 15:51 ` [PATCH 1/7] kernel: don't call do_exit() for PF_IO_WORKER threads Jens Axboe
2021-03-26 20:43   ` Eric W. Biederman
2021-03-26 22:11     ` Jens Axboe
2021-03-26 15:51 ` [PATCH 2/7] io_uring: handle signals for IO threads like a normal thread Jens Axboe
2021-03-26 20:29   ` Eric W. Biederman
2021-03-26 22:14     ` Jens Axboe
2021-03-26 22:23       ` Eric W. Biederman
2021-03-26 22:30         ` Jens Axboe
2021-03-26 22:35           ` Eric W. Biederman
2021-03-26 22:38             ` Jens Axboe
2021-03-26 22:49               ` Jens Axboe
2021-03-27 17:40                 ` Eric W. Biederman
2021-03-27 20:08                   ` Jens Axboe
2021-03-26 15:51 ` [PATCH 03/10] Revert "signal: don't allow sending any signals to PF_IO_WORKER threads" Jens Axboe
2021-03-26 15:51 ` Jens Axboe [this message]
2021-03-26 20:44   ` [PATCH 3/7] kernel: stop masking signals in create_io_thread() Eric W. Biederman
2021-03-26 15:51 ` [PATCH 04/10] Revert "kernel: treat PF_IO_WORKER like PF_KTHREAD for ptrace/signals" Jens Axboe
2021-03-26 15:51 ` [PATCH 4/7] Revert "signal: don't allow sending any signals to PF_IO_WORKER threads" Jens Axboe
2021-03-26 15:51 ` [PATCH 05/10] Revert "kernel: freezer should treat PF_IO_WORKER like PF_KTHREAD for freezing" Jens Axboe
2021-03-26 15:51 ` [PATCH 5/7] Revert "kernel: treat PF_IO_WORKER like PF_KTHREAD for ptrace/signals" Jens Axboe
2021-03-26 15:51 ` [PATCH 6/7] Revert "kernel: freezer should treat PF_IO_WORKER like PF_KTHREAD for freezing" Jens Axboe
2021-03-26 15:51 ` [PATCH 06/10] Revert "signal: don't allow STOP on PF_IO_WORKER threads" Jens Axboe
2021-03-26 15:51 ` [PATCH 7/7] " Jens Axboe
2021-03-26 15:51 ` [PATCH 07/10] io_uring: fix timeout cancel return code Jens Axboe
2021-03-26 15:51 ` [PATCH 08/10] io_uring: do post-completion chore on t-out cancel Jens Axboe
2021-03-26 15:51 ` [PATCH 09/10] io_uring: don't cancel-track common timeouts Jens Axboe
2021-03-26 15:51 ` [PATCH 10/10] io_uring: don't cancel extra on files match Jens Axboe
2021-03-26 15:54 ` [PATCHSET v2 0/7] Allow signals for IO threads Jens Axboe

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