From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0728E273816 for ; Sat, 4 Apr 2026 14:34:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775313255; cv=none; b=P8AUTtf9xI1fwL6vHLQpYqSU1zkpmxRDUVVPVR66PGXHahDGhKrVMIZdjYha5ogt8qI5eU2JYZ0mMBOkLkRDoQFOW4j0uZBtk2qb1J/li0wDeB/kw9PNu84WsSLjdxgnb4E5XpDBAKBNgRYnn/AclICcjd1xlg07zIEEP6AnsDY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1775313255; c=relaxed/simple; bh=ute7Uj0efECLnFZ3zuCKKMN2VHwq4zZE/EL48m7Di64=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Un/l8wIKzmqxOViS3m/LdxK2V7gpxWd51fDuVqjE0hU4ssp+f8FU+UtHpZfFAt7IgavNNrsp8Dz8HPzRNwmz5v1bv1nY34WvDhYK7hEqI2CD5NE5jd5CUJBKZ3MaQqrILeWF0praG6rDSeASIb5Up83A4BJL8wEGwq4TQaukFmY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=hmRUZex7; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="hmRUZex7" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1775313251; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=ute7Uj0efECLnFZ3zuCKKMN2VHwq4zZE/EL48m7Di64=; b=hmRUZex7gIvx0E4PnJbPKcIsqo9jjOrjYWlA4hwO//ESyVqgVkBEFIKGTk1/e/u35UVEuh ycrduMsLHsMFuD07So0FLqvTSvZk/JX4Htu6bE4TEV9vR2ucgneiOFZnN4tmZlX7Ceg3Yy KKbvW/VvQBCDS218lj3nyz3HYDlNqjg= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-541-NE7odKNxNNeDm5vtzRayxg-1; Sat, 04 Apr 2026 10:34:06 -0400 X-MC-Unique: NE7odKNxNNeDm5vtzRayxg-1 X-Mimecast-MFC-AGG-ID: NE7odKNxNNeDm5vtzRayxg_1775313244 Received: from mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.111]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 303C618005B0; Sat, 4 Apr 2026 14:34:04 +0000 (UTC) Received: from fedora (unknown [10.44.32.11]) by mx-prod-int-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 2D6681800361; Sat, 4 Apr 2026 14:33:59 +0000 (UTC) Received: by fedora (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Sat, 4 Apr 2026 16:34:03 +0200 (CEST) Date: Sat, 4 Apr 2026 16:33:58 +0200 From: Oleg Nesterov To: Kusaram Devineni Cc: Kees Cook , Andrew Morton , Andy Lutomirski , Peter Zijlstra , Thomas Gleixner , Will Drewry , Max Ver , linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] ptrace: don't report syscall-exit if the tracee was killed by seccomp Message-ID: References: <6E69C3F0-0691-4115-AE36-F5E5743C942A@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.111 On 04/03, Kusaram Devineni wrote: > > On 03-04-2026 21:18, Oleg Nesterov wrote: > > > seccomp does force_sig_seccomp() sends the signal to current, current > can't > > return to usermode and call signalfd_dequeue(), get_signal() must dequeue > > SIGSYS and notice SA_IMMUTABLE. > > > And since this signal is private, signalfd_dequeue() from another thread > can't > > dequeue it either. > > > No? > > Right Oleg, not by returning to userspace and calling signalfd_dequeue() > afterward, > and not from another thread. > > We identified a case when working on a syzbot bug > https://syzbot.org/bug?extid=0a4c46806941297fecb9 where the forced SIGSYS > was > consumed through the signalfd path from task_work on the same task before > get_signal() > handled normal fatal delivery. The setup there had an outstanding > io_uring-driven signalfd Aaah... Thanks again. OK, this is another (although related) issue, lets discuss it separately. > For that specific path, one approach that seems to work is making signalfd > exclude > SA_IMMUTABLE signals from the mask it passes to Perhaps... But this is nasty. May be something like "brute force" hack I sent to syzbot can work... Oleg.