From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from sipsolutions.net (s3.sipsolutions.net [168.119.38.16]) (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 29FE0295D95; Tue, 17 Jun 2025 09:50:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=168.119.38.16 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750153837; cv=none; b=MNV+u6sHxj7dNPiWVzU2syuFs0EIxdEu7vtc2ocm0/8a60AuaZNhV5VVkzPm1avW0SV8hJgvvVTpK6mAs4u9taMa25Ma2v6lnYN88zDfQlDXpQvZ1c1L27Tk0s07QIGwsmsOao89zgzb6HbBMMPwssQzVr45p1Uw+opfJKD6w3o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1750153837; c=relaxed/simple; bh=lCvXiGlCxi8K96upupQrhg6ZesjBOryzIFfMfPNEc+E=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=OVD3QXC78zIH+zROkkbyBTNN95hrYZxoFPh4e2fpT9+jaIS3LOO4qSTJG3DNO1cCmyFf52SOnBZVXEORVCLdhwcN4yNoK/lY+JtvAps9PAH8Y+ZgI4yMyEwmUBuV8ZtsYNxyQChAf/9nuGCl5ly6+cYCV1kUWS7az+Vw1rdOabI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sipsolutions.net; spf=pass smtp.mailfrom=sipsolutions.net; dkim=pass (2048-bit key) header.d=sipsolutions.net header.i=@sipsolutions.net header.b=hlMtSG46; arc=none smtp.client-ip=168.119.38.16 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sipsolutions.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sipsolutions.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=sipsolutions.net header.i=@sipsolutions.net header.b="hlMtSG46" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sipsolutions.net; s=mail; h=MIME-Version:Content-Transfer-Encoding: Content-Type:References:In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From:Resent-To: Resent-Cc:Resent-Message-ID; bh=lCvXiGlCxi8K96upupQrhg6ZesjBOryzIFfMfPNEc+E=; t=1750153836; x=1751363436; b=hlMtSG46337V3rSm9Hq+WKPYWUOhANgHqNZ8FPWw3Np3qa1 hAc3WvIT5yWszdeZFN2MJnzUuPU0OBJyPjk3YEteFvDSKg/+b0aXFSyYwHDIF48oyVHnw9uSIarZX R3YBqa6wI8a5gtEK55XfHp/5E1qcN2EeVZhic49YRp3MaoqCH3ycuCFCLPC7iAOhsiqBgd1NUEC63 cc3YDJuDEF+Eh6F61V/f9kv4M5NKYpNM71Q3uN8dWXj/BOVf60MHjuNzNZiUReci4XAvXvfZDOie7 yMy5URtS/YxLf4g5EqmQoRbzkTzewZmQ4uNOmT7vN2kr+mkxA0Y2widNnUM218fg==; Received: by sipsolutions.net with esmtpsa (TLS1.3:ECDHE_X25519__RSA_PSS_RSAE_SHA256__AES_256_GCM:256) (Exim 4.98.2) (envelope-from ) id 1uRSxd-0000000EFbx-3DuP; Tue, 17 Jun 2025 11:50:33 +0200 Message-ID: <49456d11ed8d4ff3adc71286b17dc657a6db131b.camel@sipsolutions.net> Subject: Re: [syzbot] [wireless?] WARNING: net/mac80211/tx.c:LINE at __ieee80211_beacon_get, CPU: syz.NUM.NUM/NUM From: Johannes Berg To: Aleksandr Nogikh Cc: syzbot , linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com Date: Tue, 17 Jun 2025 11:50:32 +0200 In-Reply-To: (sfid-20250617_114851_219552_D4A7444C) References: <6850d3bd.a70a0220.395abc.01fa.GAE@google.com> <97d6493279ab5c63e8844e8b0f349b2528d2832b.camel@sipsolutions.net> (sfid-20250617_114851_219552_D4A7444C) Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.56.2 (3.56.2-1.fc42) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-malware-bazaar: not-scanned On Tue, 2025-06-17 at 11:48 +0200, Aleksandr Nogikh wrote: > On Tue, Jun 17, 2025 at 11:43=E2=80=AFAM Johannes Berg > wrote: > >=20 > > On Tue, 2025-06-17 at 11:34 +0200, Aleksandr Nogikh wrote: > > > #syz dup: WARNING in __ieee80211_beacon_get > > >=20 > >=20 > > Not just this one :) > >=20 > > https://lore.kernel.org/linux-wireless/20250617104902.146e10919be1.I85f= 352ca4a2dce6f556e5ff45ceaa5f3769cb5ce@changeid/ > >=20 >=20 > Ah, interesting :) >=20 > FWIW, in this particular case, syzbot sent the duplicate report > because the WARNING format has somewhat changed in the latest > linux-next. So before we updated syzbot's parsing rules, it had > managed to re-report quite a few duplicates. Right, I had noticed that, but then I looked and the old counter is already at well over 100k so I decided to finally look at it again ;-) This is a really long-standing problem that we discussed a few times in the past I think, and basically the system is loaded enough that the hwsim hrtimer can fire on time and pull the beacon, but the workqueues are overloaded and cannot do the necessary work within the ~100ms beacon interval ... Should be rare in practice, but a WARN_ON() that doesn't say anything about what's going on doesn't help anyway. johannes