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Biederman) To: Stefan Metzmacher Cc: Sasha Levin , linux-kernel@vger.kernel.org, stable@vger.kernel.org, Jens Axboe References: <20210325112459.1926846-1-sashal@kernel.org> <20210325112459.1926846-43-sashal@kernel.org> Date: Thu, 25 Mar 2021 07:04:38 -0500 In-Reply-To: (Stefan Metzmacher's message of "Thu, 25 Mar 2021 12:34:18 +0100") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1lPOk6-006NWb-TI;;;mid=;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX18Lb2JrSghaFx8NMQ2AKONsIk2+oPW0fMQ= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on sa06.xmission.com X-Spam-Level: X-Spam-Status: No, score=0.5 required=8.0 tests=ALL_TRUSTED,BAYES_50, DCC_CHECK_NEGATIVE,T_TM2_M_HEADER_IN_MSG,T_TooManySym_01, T_TooManySym_02,T_TooManySym_03,XMSubLong autolearn=disabled version=3.4.2 X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.8 BAYES_50 BODY: Bayes spam probability is 40 to 60% * [score: 0.4829] * 0.7 XMSubLong Long Subject * 0.0 T_TM2_M_HEADER_IN_MSG BODY: No description available. * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa06 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 T_TooManySym_03 6+ unique symbols in subject * 0.0 T_TooManySym_01 4+ unique symbols in subject * 0.0 T_TooManySym_02 5+ unique symbols in subject X-Spam-DCC: XMission; sa06 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Stefan Metzmacher X-Spam-Relay-Country: X-Spam-Timing: total 433 ms - load_scoreonly_sql: 0.06 (0.0%), signal_user_changed: 10 (2.2%), b_tie_ro: 8 (1.9%), parse: 0.81 (0.2%), extract_message_metadata: 17 (3.9%), get_uri_detail_list: 1.41 (0.3%), tests_pri_-1000: 21 (4.9%), tests_pri_-950: 1.29 (0.3%), tests_pri_-900: 1.02 (0.2%), tests_pri_-90: 145 (33.5%), check_bayes: 144 (33.2%), b_tokenize: 6 (1.5%), b_tok_get_all: 6 (1.5%), b_comp_prob: 2.1 (0.5%), b_tok_touch_all: 126 (29.0%), b_finish: 0.85 (0.2%), tests_pri_0: 225 (51.9%), check_dkim_signature: 0.57 (0.1%), check_dkim_adsp: 2.1 (0.5%), poll_dns_idle: 0.51 (0.1%), tests_pri_10: 2.2 (0.5%), tests_pri_500: 7 (1.7%), rewrite_mail: 0.00 (0.0%) Subject: Re: [PATCH AUTOSEL 5.11 43/44] signal: don't allow STOP on PF_IO_WORKER threads X-SA-Exim-Version: 4.2.1 (built Sat, 08 Feb 2020 21:53:50 +0000) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Stefan Metzmacher writes: > Am 25.03.21 um 12:24 schrieb Sasha Levin: >> From: "Eric W. Biederman" >> >> [ Upstream commit 4db4b1a0d1779dc159f7b87feb97030ec0b12597 ] >> >> Just like we don't allow normal signals to IO threads, don't deliver a >> STOP to a task that has PF_IO_WORKER set. The IO threads don't take >> signals in general, and have no means of flushing out a stop either. >> >> Longer term, we may want to look into allowing stop of these threads, >> as it relates to eg process freezing. For now, this prevents a spin >> issue if a SIGSTOP is delivered to the parent task. >> >> Reported-by: Stefan Metzmacher >> Signed-off-by: Jens Axboe >> Signed-off-by: "Eric W. Biederman" >> Signed-off-by: Sasha Levin >> --- >> kernel/signal.c | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/kernel/signal.c b/kernel/signal.c >> index 55526b941011..00a3840f6037 100644 >> --- a/kernel/signal.c >> +++ b/kernel/signal.c >> @@ -288,7 +288,8 @@ bool task_set_jobctl_pending(struct task_struct *task, unsigned long mask) >> JOBCTL_STOP_SIGMASK | JOBCTL_TRAPPING)); >> BUG_ON((mask & JOBCTL_TRAPPING) && !(mask & JOBCTL_PENDING_MASK)); >> >> - if (unlikely(fatal_signal_pending(task) || (task->flags & PF_EXITING))) >> + if (unlikely(fatal_signal_pending(task) || >> + (task->flags & (PF_EXITING | PF_IO_WORKER)))) >> return false; >> >> if (mask & JOBCTL_STOP_SIGMASK) >> > > Again, why is this proposed for 5.11 and 5.10 already? Has the bit about the io worker kthreads been backported? If so this isn't horrible. If not this is nonsense. Eric