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[188.141.5.72]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-45eb6d48e23sm31544499f8f.20.2026.05.25.22.54.02 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 25 May 2026 22:54:02 -0700 (PDT) From: David Carlier To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Dave Airlie , Keith Packard , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, syzkaller-bugs@googlegroups.com, syzbot+5d32c8bd82427f9c77cc@syzkaller.appspotmail.com, David Carlier Subject: [PATCH] drm/lease: cap object_count to avoid order > MAX_PAGE_ORDER warning Date: Tue, 26 May 2026 06:53:59 +0100 Message-ID: <20260526055359.17392-1-devnexen@gmail.com> X-Mailer: git-send-email 2.53.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Stat-Signature: 3axcp3kei4ze8mcczx7rzrsqdb4puapq X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 3443B16000A X-HE-Tag: 1779774844-626233 X-HE-Meta: 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 co33e2xF 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: cl->object_count comes from userspace unbounded and reaches kzalloc_objs() in fill_object_idr(); a large value trips WARN_ON_ONCE_GFP in __alloc_frozen_pages_noprof(), letting a DRM master produce a kernel splat. Bound object_count at the ioctl entry so the page allocator is never asked for an absurd order. Reported-by: syzbot+5d32c8bd82427f9c77cc@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=5d32c8bd82427f9c77cc Fixes: 62884cd386b8 ("drm: Add four ioctls for managing drm mode object leases [v7]") Signed-off-by: David Carlier --- drivers/gpu/drm/drm_lease.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/drivers/gpu/drm/drm_lease.c b/drivers/gpu/drm/drm_lease.c index 5d2cf724cbd7..bdec759187d9 100644 --- a/drivers/gpu/drm/drm_lease.c +++ b/drivers/gpu/drm/drm_lease.c @@ -466,6 +466,13 @@ static int fill_object_idr(struct drm_device *dev, return ret; } +/* + * Upper bound on the number of objects a single lease can reference. + * Real workloads use a handful; this is set well above any plausible + * value to avoid kmalloc requests that would exceed MAX_PAGE_ORDER. + */ +#define DRM_MAX_LEASE_OBJECTS 4096 + /* * The master associated with the specified file will have a lease * created containing the objects specified in the ioctl structure. @@ -505,6 +512,12 @@ int drm_mode_create_lease_ioctl(struct drm_device *dev, } object_count = cl->object_count; + if (unlikely(object_count > DRM_MAX_LEASE_OBJECTS)) { + drm_dbg_lease(dev, "object_count %zu exceeds max %u\n", + object_count, DRM_MAX_LEASE_OBJECTS); + ret = -EINVAL; + goto out_lessor; + } /* Handle leased objects, if any */ idr_init(&leases); -- 2.53.0