From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 1C6744964E; Fri, 11 Apr 2025 13:22:52 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744377773; cv=none; b=kkrk9/SG2Uh3JoRUGNROlce0kgYp9eyxb7UFoVpj1nC4rMbARCX5hxp8ozgAr0LdcQUVeE/KmhoSUC2WPbeuDSzQFo3AmfhWrhqA4acaziTb70hEvm/fPL8meytJUhXv/esFE4rFuFZzqufW4pwsHONqUZ3MRnhk0zuvP8VbDd4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744377773; c=relaxed/simple; bh=ly6rpIyPaDRJfWGU1MeNR1JLAEhIsdS0hC/xHmLN0+A=; h=From:Subject:Date:Message-Id:MIME-Version:Content-Type:To:Cc; b=SZCt1L74rDuYqCiWSVACga/ZNGyuFQWrARN1vdtyC/2oihyMQwA2/qT7AynEWouk4Rd6Ye3fgk1mmu75oSpRjyICVCy91JFKiuMbRT7GJGrBC4EBqjauEiIs4JS0taIfnaPTWDcvPspTd4sRDRn61C/Kwvo/nBMWoZNp5DqGpfM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Ziyk9fec; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="Ziyk9fec" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 89274C4CEE2; Fri, 11 Apr 2025 13:22:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1744377772; bh=ly6rpIyPaDRJfWGU1MeNR1JLAEhIsdS0hC/xHmLN0+A=; h=From:Subject:Date:To:Cc:From; b=Ziyk9fecgjkeEfcj+/L5o69uJjmjr4ZuqM70FwcN42IAD1QBDh/e4UYEZCcREGYjB 9/P6pdodGdMbOWdH5O0oeaStONBNqpR6Zd6Sb8rZtNrKnBS53kb9biBQHGvZrOlcUQ e0+tgaPrkQUm+kwAPKMBF1QEENh78MtvHe8xipPWV0SafP5EeGyBJX6u4cbiuRba49 Tcx/itOFAP1ipUORlDw5zmeGW9L3Su4xaRvW49c2h4Q6p9BQjVLEmiLQ3GwoCZwkXU 06M1J8be9u8e77KDzeBdHoo0GLYavGQGyOi4HemUwhHN5PITOCKPIQdua6Jsct5Yh1 swU0PXSu9uVUQ== From: Christian Brauner Subject: [PATCH v2 0/2] pidfs: ensure consistent ENOENT/ESRCH reporting Date: Fri, 11 Apr 2025 15:22:43 +0200 Message-Id: <20250411-work-pidfs-enoent-v2-0-60b2d3bb545f@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="utf-8" Content-Transfer-Encoding: 7bit X-B4-Tracking: v=1; b=H4sIAKMX+WcC/yXMQQqDMBCF4avIrDuSBG3aXqW4iHGsQ2EiE6kF8 e6NdvnDe98GmZQpw6PaQOnDmZOUcJcK4hTkRchDaXDGtaaxFtekb5x5GDOSJJIFfeNbf7dXE28 Rym9WGvl7ms+udB8yYa9B4nRIB1CfQP2f7fsP6ktxsIYAAAA= X-Change-ID: 20250411-work-pidfs-enoent-747579160c8c To: Oleg Nesterov Cc: linux-fsdevel@vger.kernel.org, Jeff Layton , Lennart Poettering , Daan De Meyer , Mike Yuan , linux-kernel@vger.kernel.org, Peter Ziljstra , Christian Brauner X-Mailer: b4 0.15-dev-c25d1 X-Developer-Signature: v=1; a=openpgp-sha256; l=1002; i=brauner@kernel.org; h=from:subject:message-id; bh=ly6rpIyPaDRJfWGU1MeNR1JLAEhIsdS0hC/xHmLN0+A=; b=owGbwMvMwCU28Zj0gdSKO4sYT6slMaT/FF81da06o8yljJApy5g0trYc/xeQUnP+47siNS/TG yK9NwMkOkpZGMS4GGTFFFkc2k3C5ZbzVGw2ytSAmcPKBDKEgYtTACbipMfIcFyyqpcvwnKblMX7 sNl/P8+e5Ljw25as7PKXW88s5shf2sXwVyb1wKm4bQ4Czc9XvHp6mmWr3lzpvRa/X+2O89r358Z KUW4A X-Developer-Key: i=brauner@kernel.org; a=openpgp; fpr=4880B8C9BD0E5106FC070F4F7B3C391EFEA93624 In a prior patch series we tried to cleanly differentiate between: (1) The task has already been reaped. (2) The caller requested a pidfd for a thread-group leader but the pid actually references a struct pid that isn't used as a thread-group leader. as this was causing issues for non-threaded workloads. But there's cases where the current simple logic is wrong. Specifically, if the pid was a leader pid and the check races with __unhash_process(). Stabilize this by using the pidfd waitqueue lock. Signed-off-by: Christian Brauner --- Christian Brauner (2): exit: move wake_up_all() pidfd waiters into __unhash_process() pidfs: ensure consistent ENOENT/ESRCH reporting kernel/exit.c | 5 +++++ kernel/fork.c | 31 +++++++++++++------------------ kernel/pid.c | 5 ----- 3 files changed, 18 insertions(+), 23 deletions(-) --- base-commit: 1e940fff94374d04b6c34f896ed9fbad3d2fb706 change-id: 20250411-work-pidfs-enoent-747579160c8c