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bh=XYN8f9351KWFfUArUzuNWsE73Ym72FcZGNNmApexyGU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=R3Rvm3fVI8htPpnQ/F2ytZ3FU7ZNFrH2CIc4cyuf1q/fdwKwnduQu51H3ysvqAkMB Q1KKixl5zk3jvHhOOV2F4E61EKZFa7oG/PA9706muY7ywY9BupuBgHDD1yNFnDGuaW FGuR+FtkcAgBwN/SbyUjRawr/iiTB7Z4GYOEj7nFW4qSlnboRhZQncqQ6a3T5IRboD TTYEibbrSoD+9YS4NmwdwSDjG3qRdSNdlczR0s9hxVfN02zuSM/QVkW0XjOzwAAQPe Fz/PBD0+DGg/Arz4lLN5rGEfhlhLCW+hIAhRxbFdOa02AJQAHHyJh6v3Y+61aq0MVr tLoHh40zwvoFA== From: SJ Park To: Hari Mishal Cc: SJ Park , Shuah Khan , Greg Kroah-Hartman , damon@lists.linux.dev, linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] selftests/damon/sysfs.py: clean up sh processes used for obsolete_target test Date: Tue, 21 Jul 2026 16:51:52 -0700 Message-ID: <20260721235153.149569-1-sj@kernel.org> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260721190404.135937-1-harimishal1@gmail.com> References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: 25E30180003 X-Stat-Signature: py59c85uugzrwcr4ifi7krpkres5u3hh X-Rspam-User: X-HE-Tag: 1784677922-563445 X-HE-Meta: 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 jpN3hhjx DzM+7AmIYEVp2i7gp8lcNBzrOp9toCUqwd5VCQoLPAEZRcKIsWU12HJUwM7B5e02YIwBJO4gPYxaW/Jya7p8aDdLMcvGP3qUPt8l99PfD0ksjyDksKMO81p0m4RKn9+yQpqm2CaS/fzKZ8asPZfeZgR7WSUxluUj1A9xgWOUkvSDuySamYW8ZG5Aiot4hXcfZ3FVW0nTXV+MhfwQxBRteYM2vY20181J5e4q8s8ZRLl3Rv/3afB1qxo30I0LoNuvT4f+NOR/wIAzKvfO12KlC0chO0w== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hello Hari, On Tue, 21 Jul 2026 21:04:04 +0200 Hari Mishal wrote: > The obsolete_target test spawns three sh processes and uses their pids > as DAMON monitoring targets. These processes are created without their > own stdin, so they inherit the test program's stdin, and they are never > waited on or told to exit. As a result, they are left running (or > become zombies) as orphaned children after the test program exits. Thank you for finding this problem and sharing this great patch! > > Give each sh process its own dedicated stdin pipe instead of inheriting > the test program's, and after the targets are no longer needed, > communicate() with each process to close its stdin. This sends EOF to > the shell, which makes it exit, and communicate() then reaps the > process. Can't we use terminate() or kill() instead of communicate()? Thanks, SJ [...]