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AJvYcCUJVVYxQxYdfIGVMzIYWwg7+xK3arYpMoNaOCIWc8kDQHe6DIIhbAmGL+F08ii5ztUsO/uJ2QrV6Q==@kvack.org X-Gm-Message-State: AOJu0YxwpxImRhisYuCw6620KWxfCq10UOwPFTmwFH0NNGKWeA1eTezH UXe99AgC2LOHuvOUtWZ/I3zmv207jZAWK2tYYxBcuJwvIgMdexmP1nJF46lKkNzRfk/oppiDJ7p nc2iDyKfI9liektYirj8v67uFeBNY6kHel+rEdCMB X-Gm-Gg: ASbGncs53OEP1GwB75jwbzZ9EDFzN8U8tHFPM5q1XO0iKjBi12tQh+ROzAMv+Djebi0 7aQnRJqx2CBDPM3S8A2nb7t1DulkJtJbr/WCWq4NnqkFVHu2bWzzzWT4rz5vP4W3Sm0wEYorv0b H4Jq9ZQkWU3g1bphZYVGW48WeMq1zOJ0bsPAcM/aDcOe6a/wU3RoXtCE6p+olHJMeoQRysqOJA1 EyrzgITjDy932ZXi5jB9oOddn23ouYb7sp7cyPQbgMT8UwtyQZQuIWaT3LfmX6Xo0plrNQWIx2l 4XeRx6mNVi5uywhsm+0= X-Google-Smtp-Source: AGHT+IEAICGtm6NZwDsByzAJ38ijLdVal4l1vq6PUUUbo88S4qCmpEjKeMXQGMqibYfiyxUc7Vr67BHJv3oovdCQ47I= X-Received: by 2002:a17:902:cec3:b0:265:e66:6c10 with SMTP id d9443c01a7336-29554acb52dmr5165755ad.4.1762105801057; Sun, 02 Nov 2025 09:50:01 -0800 (PST) MIME-Version: 1.0 References: <20250917190323.3828347-1-yang@os.amperecomputing.com> <20250917190323.3828347-4-yang@os.amperecomputing.com> <933a2eff-1e06-451e-9994-757d66f4b985@arm.com> In-Reply-To: From: Guenter Roeck Date: Sun, 2 Nov 2025 09:49:50 -0800 X-Gm-Features: AWmQ_bltYJ86Q3HtfXxhBr-_kg1IjduAALHrq3mVP45Prvfz_NGkLOMlSeQlc50 Message-ID: Subject: Re: [PATCH v8 3/5] arm64: mm: support large block mapping when rodata=full To: Ryan Roberts Cc: Yang Shi , catalin.marinas@arm.com, will@kernel.org, akpm@linux-foundation.org, david@redhat.com, lorenzo.stoakes@oracle.com, ardb@kernel.org, dev.jain@arm.com, scott@os.amperecomputing.com, cl@gentwo.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, nd@arm.com Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: mhigp8x3a3ukjeuj5n37gezpw9n9wcda X-Rspamd-Queue-Id: 828B0C0005 X-Rspamd-Server: rspam06 X-Rspam-User: X-HE-Tag: 1762105802-5497 X-HE-Meta: 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 4XNRdpGO 4JH9UujenP42AGJuheMYpkb2cmIVvoxybE6aJYLtOUBzqbXbDly0mU4BW20bB5UByjvOaD1zRdDN8i0tx8bPEwPjOUzipdJQ/ESND1kRLkEf6LuehQ4yu92Hx16afEg0wurGzyDn8QcE3Zhvso46xymsyzbnp3hyGch2dwMTMAIC9G5YJQ0hjhzMaO+60P6yTk4UQDoOC9F9s42+XfF1rjIj57V53Jgy1Nn7KK4+HT9mYfuIKVgbfYlJpH9/dM4xV6N5AUsqZokKOwxFuuLPEDdIyvTRY7brtAamxahcilcQVrgTkmdv70NA0LT4i/UDiR5qwhNRKG6LyGzorMZBvX8UHkFwt7lqyS7SENe3lzjWoIhk= 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 Sun, Nov 2, 2025 at 7:09=E2=80=AFAM Ryan Roberts wr= ote: ... > commit 602ec2db74e5abfb058bd03934475ead8558eb72 > Author: Ryan Roberts > Date: Sun Nov 2 11:45:18 2025 +0000 > > arm64: mm: Don't attempt to split known pte-mapped regions > > It has been reported that split_kernel_leaf_mapping() is trying to sl= eep > in non-sleepable context. It does this when acquiring the > pgtable_split_lock mutex, when either CONFIG_DEBUG_ALLOC or > CONFIG_KFENCE are enabled, which change linear map permissions within > softirq context during memory allocation and/or freeing. > > But it turns out that the memory for which these features may attempt= to > modify the permissions is always mapped by pte, so there is no need t= o > attempt to split the mapping. So let's exit early in these cases and > avoid attempting to take the mutex. > > Closes: https://lore.kernel.org/all/f24b9032-0ec9-47b1-8b95-c0eeac7a3= 1c5@roeck-us.net/ > Fixes: a166563e7ec3 ("arm64: mm: support large block mapping when rod= ata=3Dfull") > Signed-off-by: Ryan Roberts Tested-by: Guenter Roeck Thanks a lot for the quick turnaround! Guenter