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 D985814B077 for ; Thu, 25 Apr 2024 17:21:37 +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=1714065697; cv=none; b=m+2LaHtJg7vI2Sk/+hblkPRfn0FEjneJBQ7Zu7OpCdj5PBP7vPJbqSMkiN3TftbaW4TGVKclKKe+Z6jUWXGfP1Vl0AJ9WMFUJoZgaWf/fDnpyfzl3I12EHFTfd7Q5Ku1+YceCtnPUf/plyciTPNNnM2jZNaf4eL4CdN6lFHvE7U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1714065697; c=relaxed/simple; bh=A4dvd3/faeKQINO11XK5APR21o72NsWW/xbRr+61Uj4=; h=Date:To:From:Subject:Message-Id; b=G0Q0/ofxty+xJe5Sk2Q4tZ8+nfTM9v8XJUCmU6pQNFwNrRo8KMOJlqmzfzJkPa3F0AJF3+TBLyPnYPxPuovGNLwtqtBBp9gXZe8U7S3xq94XwZRbdpPp8R4FErQAkxzEQ5RNhqGMQtNZZVroFiR3xu3rNBQXoRIVLtnhRNYO+bk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=FYN/hPY9; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="FYN/hPY9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 9C9DAC113CC; Thu, 25 Apr 2024 17:21:37 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1714065697; bh=A4dvd3/faeKQINO11XK5APR21o72NsWW/xbRr+61Uj4=; h=Date:To:From:Subject:From; b=FYN/hPY9xTNpXA06rsZhW1MUxQFu1EVolcNAcGFjw1TmSJMwROEVAnV7bDZR/XVc1 FElkB4CJ/MMpgjiuO0ogbh84yDddIW2gMfg306/ZIJJSnetRrHowGpz6tAcs6OF17q FoT7v6zBmyoloFbQqo1Cx4sJWDDDKr9GJ5BxHfl0= Date: Thu, 25 Apr 2024 10:21:37 -0700 To: mm-commits@vger.kernel.org,palmer@rivosinc.com,Kuan-Ying.Lee@mediatek.com,kbingham@kernel.org,jan.kiszka@siemens.com,debug@rivosinc.com,ajones@ventanamicro.com,mail@florommel.de,akpm@linux-foundation.org From: Andrew Morton Subject: + scripts-gdb-fix-detection-of-current-cpu-in-kgdb.patch added to mm-nonmm-unstable branch Message-Id: <20240425172137.9C9DAC113CC@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: scripts/gdb: fix detection of current CPU in KGDB has been added to the -mm mm-nonmm-unstable branch. Its filename is scripts-gdb-fix-detection-of-current-cpu-in-kgdb.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/scripts-gdb-fix-detection-of-current-cpu-in-kgdb.patch This patch will later appear in the mm-nonmm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Florian Rommel Subject: scripts/gdb: fix detection of current CPU in KGDB Date: Thu, 25 Apr 2024 17:35:01 +0200 Directly read the current CPU number from the kgdb_active variable. Before, the active CPU was obtained through the current task, which required searching the task list for the pid of GDB's selected thread. Obtaining the pid was buggy: GDB may use selected_thread().ptid[1] (LWPID) instead of .ptid[2] (TID) to store the threads pid; see https://sourceware.org/gdb/current/onlinedocs/gdb.html/Threads-In-Python.html As a result, the detection could return the wrong CPU number, leading to incorrect results for $lx_per_cpu and $lx_current. As a side effect, the patch significantly speeds up $lx_per_cpu and $lx_current in KGDB by avoiding the task-list iteration. Link: https://lkml.kernel.org/r/20240425153501.749966-5-mail@florommel.de Signed-off-by: Florian Rommel Cc: Andrew Jones Cc: Deepak Gupta Cc: Jan Kiszka Cc: Kieran Bingham Cc: Kuan-Ying Lee Cc: Palmer Dabbelt Signed-off-by: Andrew Morton --- scripts/gdb/linux/cpus.py | 6 +----- 1 file changed, 1 insertion(+), 5 deletions(-) --- a/scripts/gdb/linux/cpus.py~scripts-gdb-fix-detection-of-current-cpu-in-kgdb +++ a/scripts/gdb/linux/cpus.py @@ -26,11 +26,7 @@ def get_current_cpu(): if utils.get_gdbserver_type() == utils.GDBSERVER_QEMU: return gdb.selected_thread().num - 1 elif utils.get_gdbserver_type() == utils.GDBSERVER_KGDB: - tid = gdb.selected_thread().ptid[2] - if tid > (0x100000000 - MAX_CPUS - 2): - return 0x100000000 - tid - 2 - else: - return tasks.get_thread_info(tasks.get_task_by_pid(tid))['cpu'] + return gdb.parse_and_eval("kgdb_active.counter") else: raise gdb.GdbError("Sorry, obtaining the current CPU is not yet " "supported with this gdb server.") _ Patches currently in -mm which might be from mail@florommel.de are scripts-gdb-fix-failing-kgdb-detection-during-probe.patch scripts-gdb-fix-parameter-handling-in-lx_per_cpu.patch scripts-gdb-make-get_thread_info-accept-pointers.patch scripts-gdb-fix-detection-of-current-cpu-in-kgdb.patch