From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=166.70.13.232 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792700494; b=cW1BkOrtXGu9g3J+1cHRqdLqZquC4nsL5NgiEmdGAiS5+0NXfL3NYSVui5IbN/qNcsRB SNpy4vHqLzC29eMxaLKRU8xKXLGPiOLBE3VVhkmseANBeldesGgwcAQ7xiYiNtTiMvhqd YfPAu8JwQnApvJrsxEpoMEnMtE3E1EO14BRelUH+adBY1KkAXzsYsZbSTE3LL22YapzJN wAxqUUf7DlU6tn6nFA2ocgCnPsYKsXq4bELjul7Gk8ilkUbl2cnLvz9XSxrHpQLuqGJJN UX0zWeIW7V4JDuCx7zbKO+MRcKUQqfXVNcB17b/WPbuP4IC5laSClTLyT/n8sKf9Bnw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792700494; h=DMARC-Filter:DKIM-Signature:Received:Received:From:To:Cc:In-Reply-To: References:Date:Message-ID:User-Agent:MIME-Version:Content-Type: X-XM-SPF:X-XM-AID:X-Spam-Checker-Version:X-Spam-Level:X-Spam-Status: X-Spam-Report:X-Spam-DCC:X-Spam-Combo:X-Spam-Relay-Country: X-Spam-Timing:Subject:X-SA-Exim-Connect-IP:X-SA-Exim-Rcpt-To: X-SA-Exim-Mail-From:X-SA-Exim-Scanned; bh=LcRz1Ev8DmcKSEVZ7ce9IIus/Kh4engCFXM+xi1JDXo=; b=V3MMXXAaX7N956nZw6EplPak7On+As/8jdDVk1BAZruXOqaz0Lebqgiv1Tk3x7OFigZc 20vW99cgHEtXHsOo4zJm+4KjDcL9ojFlEUGV1QI4ESP22thED/lkHv+32DWCtEZMXyIM3 qvaF+IYVnrWC8MuTdbhXoolRk9dPmwW5RnO6jSZfA6i6psrJA4YwmaQ8P4oU3qzQdARLM agQek0TOzHuHrP5qc0sRc68DnmAuunQ0YPFuU1fYPhOIcNTJbtrm6G26Hs0Ua3utNWsiQ Hs0W89XOH4YrpHwt1MS6TSKFPVKrw5SkQma+ClBy3TC6kmuTq1PK5stCrmPB1pPwbJw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=xmission.com; spf=pass smtp.mailfrom=xmission.com; dkim=pass header.d=xmission.com header.i=@xmission.com header.a=rsa-sha256 header.s=xmission header.b=MaS0idwL; arc=none smtp.remote-ip=166.70.13.232 Received: from out02.mta.xmission.com (out02.mta.xmission.com [166.70.13.232]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (prime256v1) server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6F2BB606A31A for ; Thu, 22 Oct 2026 20:21:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 6F2BB606A31A Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=xmission.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=xmission.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=xmission.com header.i=@xmission.com header.a=rsa-sha256 header.s=xmission header.b=MaS0idwL DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=simple/simple; d=xmission.com; s=xmission; h=Subject:Content-Type:MIME-Version:Message-ID:Date:References: In-Reply-To:Cc:To:From:Sender:Reply-To:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=1epwcureGNJe5lZImEmuL8jL3EcLC66Hw65Ezl9z594=; b=MaS0idwL+v+sz+ztqqVGyN+omI 0s5OI/NpokVagz1E1v03b+Mbyc7lHroUSFkf22A5kMDLHB+mmPPfgadlh2XpQrBf0uWCY9GCYUlIZ Q+B0SBmvea8tjhrRMhCs8K6UT+GEKbm+pKKHctUyo/eGhr4LjzPGROIb1aZysAl4LnMg=; Received: from in02.mta.xmission.com ([166.70.13.52]:36712) by out02.mta.xmission.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1xJzI5-0079yo-Fp; Thu, 22 Oct 2026 14:21:33 -0600 Received: from ip72-198-196-98.om.om.cox.net ([72.198.196.98]:44010 helo=email.froward.int.ebiederm.org.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1xJzI4-00FRPs-IO; Thu, 22 Oct 2026 14:21:33 -0600 From: "Eric W. Biederman" To: Oleg Nesterov Cc: Avi Weiss , Andrew Morton , Christian Brauner , linux-kernel@vger.kernel.org In-Reply-To: (Oleg Nesterov's message of "Thu, 22 Oct 2026 13:58:34 +0200") References: <20261022061015.3737924-1-thnkslprpt@gmail.com> Date: Thu, 22 Oct 2026 20:21:26 +0000 Message-ID: <878q3po5a1.fsf@email.froward.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1xJzI4-00FRPs-IO;;;mid=<878q3po5a1.fsf@email.froward.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=72.198.196.98;;;frm=ebiederm@xmission.com;;;sPfnum=0;;;sPf=pass X-XM-AID: U2FsdGVkX18JiXHqZK5E60Wmiv15NtR6CppcuNhGn+E= X-Spam-Level: X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.1 BAYES_50 BODY: Bayes spam probability is 40 to 60% * [score: 0.5000] * 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 * [sa08 1397; Body=1 Fuz1=1 Fuz2=1] * 0.0 T_TooManySym_02 5+ unique symbols in subject * 0.0 T_TooManySym_01 4+ unique symbols in subject X-Spam-DCC: XMission; sa08 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Oleg Nesterov X-Spam-Relay-Country: X-Spam-Timing: total 424 ms - load_scoreonly_sql: 0.08 (0.0%), signal_user_changed: 14 (3.2%), b_tie_ro: 12 (2.8%), parse: 0.95 (0.2%), extract_message_metadata: 4.0 (0.9%), get_uri_detail_list: 1.61 (0.4%), tests_pri_-2000: 3.8 (0.9%), tests_pri_-1000: 2.4 (0.6%), tests_pri_-950: 1.12 (0.3%), tests_pri_-900: 0.77 (0.2%), tests_pri_-90: 93 (22.0%), check_bayes: 91 (21.6%), b_tokenize: 7 (1.8%), b_tok_get_all: 9 (2.1%), b_comp_prob: 3.7 (0.9%), b_tok_touch_all: 66 (15.5%), b_finish: 1.45 (0.3%), tests_pri_0: 281 (66.3%), check_dkim_signature: 0.70 (0.2%), check_dkim_adsp: 3.5 (0.8%), poll_dns_idle: 0.75 (0.2%), tests_pri_10: 2.5 (0.6%), tests_pri_500: 12 (2.8%), rewrite_mail: 0.00 (0.0%) Subject: Re: [PATCH v2] signal: respect the blocked mask in dequeue_synchronous_signal() X-SA-Exim-Connect-IP: 166.70.13.52 X-SA-Exim-Rcpt-To: linux-kernel@vger.kernel.org, brauner@kernel.org, akpm@linux-foundation.org, thnkslprpt@gmail.com, oleg@redhat.com X-SA-Exim-Mail-From: ebiederm@xmission.com X-SA-Exim-Scanned: No (on out02.mta.xmission.com); SAEximRunCond expanded to false Oleg Nesterov writes: > I was going to send another cleanup on top of this fix. Can't do this today, > but let me explain... It is a bit ugly to check si_signo twice. I can see where your proposed change is addressing that and it seems reasonable. > And afaics we have another problem. sys_rt_sigqueueinfo() allows to > send a SI_FROMKERNEL RT signal to itself. I don't see where your proposed code is addressing this. >From 10,000 feet I think it is deliberate that we allow sending all possible pending signals to ourselves. Some version of that is necessary to restore a checkpoint of a process, if it has not yet handled the signal at the point it is check-pointed. You can look at CRIU if you need to see if this is behavior that is being relied upon. > In this case sigmask(q->info.si_signo) leads to UB on 32-bit. I presume you are referring to a signal number that exceeds 32 being put into a 32bit mask. That does seem worth fixing. Eric > I'll recheck, write the changelog, and send something like below tomorrow. > perhaps rt_sigmask() makes more sense than sigset_t... > > Oleg. > > > From 6f7441ff08d7b88b96ac6787b40634e8c173003c Mon Sep 17 00:00:00 2001 > From: Oleg Nesterov > Date: Thu, 22 Oct 2026 13:43:01 +0200 > Subject: [PATCH] signal: cleanup the .si_signo checks in dequeue_synchronous_signal() > > Signed-off-by: Oleg Nesterov > --- > kernel/signal.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/kernel/signal.c b/kernel/signal.c > index 7386b9552dc3..9cfd4d03cad4 100644 > --- a/kernel/signal.c > +++ b/kernel/signal.c > @@ -676,21 +676,24 @@ static int dequeue_synchronous_signal(kernel_siginfo_t *info) > struct task_struct *tsk = current; > struct sigpending *pending = &tsk->pending; > struct sigqueue *q, *sync = NULL; > + unsigned long mask; > + sigset_t xxx; > > /* > * Might a synchronous signal be in the queue? > */ > - if (!((pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK)) > + mask = (pending->signal.sig[0] & ~tsk->blocked.sig[0]) & SYNCHRONOUS_MASK; > + if (!mask) > return 0; > > + siginitset(&xxx, mask); > /* > * Return the first synchronous signal in the queue. > */ > list_for_each_entry(q, &pending->list, list) { > /* Synchronous signals have a positive si_code */ > - if ((q->info.si_code > SI_USER) && > - (sigmask(q->info.si_signo) & SYNCHRONOUS_MASK) && > - !sigismember(&tsk->blocked, q->info.si_signo)) { > + if (SI_FROMKERNEL(&q->info) && > + sigismember(&xxx, q->info.si_signo)) { > sync = q; > goto next; > }