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d=hostedemail.com; s=arc-20220608; t=1716969168; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=CJOLoIxbMkRo3s/P+W4lD0NHUWgCwENQNfGbsG7onwM=; b=hEGtR2hpK4bTMlCFnZbtIdhqcXuOZIOzcxEG7ObbKfybN7T+FudDejQV+Iy8CPWyUmFFYp gbQt8L/ddgFlBZlH6c4Ca3dZnYr94o8y+wRiDkeIjcozkyyAUwBTuOpn+G65g6/XDrBRav /Rf3xLh4deuBVv7Sw85QhMncxhNHJOc= Date: Wed, 29 May 2024 09:52:44 +0200 From: Ingo Saitz To: linux-mm@kvack.org Subject: Re: [linus:master] [mm] ba42b524a0: segfault_at_ip_sp_error Message-ID: References: <202405281425.92ece916-lkp@intel.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="gtXMqvjZQD7mRYE8" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: A3107180004 X-Stat-Signature: jxk69tsbq33djt5c5yghce3m1cexrz76 X-HE-Tag: 1716969167-445893 X-HE-Meta: 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 vamwyqCR aZABCBkFkKtoUsbP7GD752kBLP0zp28zhDfws0EM8jqmk+Hb4eoReli5g4ICqopl7KsdlrR4xHArfJujAqueDYOCy2bTlwSExRFYhwiwpBDIxL64sedpDKeanzPFaTzQ4I5AlqnWpzmXtohrQqWWaivCIKy6en3WcYJCCauuheh06nQ7OqyfJY1KJh8ACqbJCl6ZqZgAel180CUx9hLsjXnYcUA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: --gtXMqvjZQD7mRYE8 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit On Tue, May 28, 2024 at 10:52:41PM +0200, Ingo Saitz wrote: > I hit the same error on devuan unstable, with startpar crashing on boot: > > [ 10.025881] dracut: Switching root > [ 10.339687] startpar[720]: segfault at 0 ip 0000000000000000 sp 00007fffbdca9c38 error 14 likely on CPU 1 (core 0, socket 0) > [ 10.340225] Code: Unable to access opcode bytes at 0xffffffffffffffd6. > [ 10.349516] startpar[820]: segfault at 0 ip 0000000000000000 sp 00007ffd52c34e48 error 14 likely on CPU 3 (core 1, socket 0) > [ 10.350086] Code: Unable to access opcode bytes at 0xffffffffffffffd6. I can reproduce the error with the attached c program. [ 1325.980596] thoughts[2127]: segfault at 0 ip 0000000000000000 sp 00007fff183d66e8 error 14 likely on CPU 0 (core 0, socket 0) [ 1325.981180] Code: Unable to access opcode bytes at 0xffffffffffffffd6. Simply calling mlockall(MCL_CURRENT) and then fork() seems to be enough to trigger the error. Ingo -- const_cast(Λ) --gtXMqvjZQD7mRYE8 Content-Type: text/x-csrc; charset=us-ascii Content-Disposition: attachment; filename="thoughts.c" #define _GNU_SOURCE #include #include #include #include #include #include int main() { mlockall(MCL_CURRENT); pid_t pid = fork(); if (pid == 0) { _exit(0); } const struct timespec zero = {2, 0}; sigset_t smask; sigemptyset(&smask); pselect(0, 0, 0, 0, &zero, &smask); printf("Success on pid %d\n", pid); } --gtXMqvjZQD7mRYE8--