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b=r0zjVGZ3WfZt2lkKyK++fGQ5Uci1WGTl67tFp0SWYSLCa6sXwZ2zRFVTO4GCzk6U6 hcHRAcC5M3wPfTlEM96vQUS4BmIaa+/RErHWrO3NqkfS4BLTMs4j6ooBfMKlErkNHB oY207cL8pnPACBMpeNmg55s5wJsZSYMprq604GVSt4nLmpiGNec7S/u6jTPmpm/z9O Jbzk3pKdp4twSWcC9LCW8hzLwpUgFz0+oKDYUYmf7B+qd8g2eS5AS7redsj9MRbZTQ o4bM1mPZv9x4hclE0DjrTbc4jXYWoYRGgNDb05ytD29VpUMSpVkHAyDebL+bKDGPV5 RW8OEFINGZOeg== Date: Mon, 17 Jun 2024 16:52:45 -0700 From: Kees Cook To: Roman Kisel Cc: akpm@linux-foundation.org, apais@linux.microsoft.com, ardb@kernel.org, bigeasy@linutronix.de, brauner@kernel.org, ebiederm@xmission.com, jack@suse.cz, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, nagvijay@microsoft.com, oleg@redhat.com, tandersen@netflix.com, vincent.whitchurch@axis.com, viro@zeniv.linux.org.uk, apais@microsoft.com, ssengar@microsoft.com, sunilmut@microsoft.com, vdso@hexbites.dev Subject: Re: [PATCH 1/1] binfmt_elf, coredump: Log the reason of the failed core dumps Message-ID: <202406171649.8F31EAFE@keescook> References: <20240617234133.1167523-1-romank@linux.microsoft.com> <20240617234133.1167523-2-romank@linux.microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240617234133.1167523-2-romank@linux.microsoft.com> X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 63382100002 X-Stat-Signature: tbyafgpiqfdp1x3jeo5awp1frrfqnu3q X-Rspam-User: X-HE-Tag: 1718668367-394583 X-HE-Meta: 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 QWSZhZdt izmy4z3pLgQQHjJy6iR2eDSQYLW/kM/KiA+yIPmX2FNnN+yuEABmdKNgEa0UYvtg8TE7bvTo08XPoKS6m5lMjBL26QgBmqEn6pkknllWiFJ5lFQMIqVJuStJwMFyDQ0M/XCSogp/zkPJgR+kAgJuOLQiBA7yr74GAhxqPz2YQ/xuAB4rBr9+2HoqL5lN+lYSeM2Ni22A2tmWmscfw0cKLhwHnUxy5oeKJ3d7OWcrgxeulew+VWW8Uvo69blZpeOEGNAygm0JMNDqYZa1qAfp4uQSFsSkiTb5Hh6wPEiQOS/CW48qEdaPagJtaFPnEisrB5MJHGbhrp2xiaFgKmMYFCVi3Ks3eAcm5mI8wwnugWKPxXFQYDahSDHr6oOAdeGi3pikI X-Bogosity: Ham, tests=bogofilter, spamicity=0.001569, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon, Jun 17, 2024 at 04:41:30PM -0700, Roman Kisel wrote: > Missing, failed, or corrupted core dumps might impede crash > investigations. To improve reliability of that process and consequently > the programs themselves, one needs to trace the path from producing > a core dumpfile to analyzing it. That path starts from the core dump file > written to the disk by the kernel or to the standard input of a user > mode helper program to which the kernel streams the coredump contents. > There are cases where the kernel will interrupt writing the core out or > produce a truncated/not-well-formed core dump. Hm, I'm all for better diagnostics, but they need to be helpful and not be a risk to the system. All the added "pr_*()" calls need to use the _ratelimited variant to avoid a user inducing massive spam to the system logs. And please standardize the reporting to include information about the task that is dumping. Otherwise the logging isn't useful for anyone reading it. Something that includes pid and task->comm at the very least. :) For example, see report_mem_rw_reject() in https://lore.kernel.org/lkml/20240613133937.2352724-2-adrian.ratiu@collabora.com/ -Kees -- Kees Cook