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Biederman" Cc: Brian Mak , Alexander Viro , Christian Brauner , Jan Kara , "linux-fsdevel@vger.kernel.org" , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , Oleg Nesterov , Linus Torvalds Subject: Re: [PATCH v3] binfmt_elf: Dump smaller VMAs first in ELF cores Message-ID: <202408121105.E056E92@keescook> References: <036CD6AE-C560-4FC7-9B02-ADD08E380DC9@juniper.net> <87ttfs1s03.fsf@email.froward.int.ebiederm.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87ttfs1s03.fsf@email.froward.int.ebiederm.org> X-Rspam-User: X-Stat-Signature: k6qqnsg6axrdu9tqa14pxsbshqqdazsg X-Rspamd-Queue-Id: 3F27D40008 X-Rspamd-Server: rspam11 X-HE-Tag: 1723485945-262957 X-HE-Meta: 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 CpVKVIK7 zbjj8Qi8phdHm6pt5t8qW0cNm3k0FJyybt6Kvlod+qeJ02XK2v44RnxiVuspL3vSvcr7R7vtZx7aePq74holco7CBP5xztjKADycsXPHG31YBofN8+G1yUZDc83IXfdHOVPvcdWPGYYCwEaijQFqRqk0UuUasaNvHtizZFsMzUMWMUNg2YfvIcU8QUwovot+oOi928Ytoqo9JdMPOyoefVdD28DxLXhZOLIlXHY0hQk5dLUQ2+wzKQZqE8o9BsPCfUMhPSYYD3Ro/HKFoL+7gELlIPocddt6NMbFpumevUqZLlVSYmvgPhkQEKwOpVH+zV+B4wuSUNj/bPpCUo3eC9pvw+ImRexNPCo4lGsMFpOoj3SphgBgDZNqcuVdMLckzARuN6GnjDZyzupEcTY+5PIwvuiGidsagg5bAxsMc6kX4GGs4snN3jUEIZoCQMfsRIntsPpFMNPHQ6IhzK9yktWW2AoLvFNZnuqFf8zk8Jmpn/xU= 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: On Sat, Aug 10, 2024 at 07:28:44AM -0500, Eric W. Biederman wrote: > Brian Mak writes: > > > Large cores may be truncated in some scenarios, such as with daemons > > with stop timeouts that are not large enough or lack of disk space. This > > impacts debuggability with large core dumps since critical information > > necessary to form a usable backtrace, such as stacks and shared library > > information, are omitted. > > > > We attempted to figure out which VMAs are needed to create a useful > > backtrace, and it turned out to be a non-trivial problem. Instead, we > > try simply sorting the VMAs by size, which has the intended effect. > > > > By sorting VMAs by dump size and dumping in that order, we have a > > simple, yet effective heuristic. > > To make finding the history easier I would include: > v1: https://lkml.kernel.org/r/CB8195AE-518D-44C9-9841-B2694A5C4002@juniper.net > v2: https://lkml.kernel.org/r/C21B229F-D1E6-4E44-B506-A5ED4019A9DE@juniper.net > > Acked-by: "Eric W. Biederman" > > As Kees has already picked this up this is quite possibly silly. > But *shrug* that was when I was out. I've updated the trailers. Thanks for the review! -Kees -- Kees Cook