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AJvYcCUc7Em2YZUS4NOE6IY3+0+jjwLFGB3ho5CpCmwIZfH2JDbW6a75dMf5KMWBMW+q4KSoeJppReXzBw==@kvack.org X-Gm-Message-State: AOJu0YxZpO7czfh4oThs2DwiunUD2I1RYAQujnPoytbPbTW+msXrAIJN ZakzBJH2Kr7ZOhxY2U9/9B6Cwx5JwQ5ZUwUW6tR2ilKaIbPc6PD6wo/+1aBG1E3WIq9vnC/T1sD isuV6gl7wawOJcTYfW4Fn8TbEpls= X-Gm-Gg: ASbGnctmT7XNkznF2pLLC0o3n6v+QV75i4eMFTAgwWZDErTCJTE5y9fjABFSrYDsoHW niIH0aOPI4l6Sc3+yFHlkXwYv2RpblUkisufGAjbX4aiXEW2t+mjZ/1Si6ViE1K1EL09e+ejUSv BiCjeQcwFhVqQFGGl2vL1XqrXsNGQ= X-Google-Smtp-Source: AGHT+IG3fmHz2E+6aMtRT6NZtv0M4VNelZBA1J0TIg1co0vQFmeR6ifavyyfyKBLbGkyrmm4MYHT38YxPlA2+orv6kk= X-Received: by 2002:a5d:64e4:0:b0:38d:be5e:b2a7 with SMTP id ffacd0b85a97d-38dea2e98e7mr967564f8f.10.1739361555145; Wed, 12 Feb 2025 03:59:15 -0800 (PST) MIME-Version: 1.0 References: <20250211160750.1301353-1-longman@redhat.com> In-Reply-To: <20250211160750.1301353-1-longman@redhat.com> From: Andrey Ryabinin Date: Wed, 12 Feb 2025 12:59:01 +0100 X-Gm-Features: AWEUYZnaqmNFQ_lbBc6EZt7NZdSpHvlmvNFB56VaHucCrwmsBCcCq_pnMuQNjtc Message-ID: Subject: Re: [PATCH] kasan: Don't call find_vm_area() in RT kernel To: Waiman Long Cc: Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , Andrew Morton , Sebastian Andrzej Siewior , Clark Williams , Steven Rostedt , kasan-dev@googlegroups.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, Nico Pache Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Stat-Signature: rzrqp1gdzadkh9kkjmzarmgtnyzh4jfg X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: B9C36180007 X-Rspam-User: X-HE-Tag: 1739361556-572526 X-HE-Meta: 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 Wd1RH2WI 5Yhcp78XCvXTvI7QXM6l7DrqewF7tgPo/PA2AuSULlHGHIcNA4KMhDDeURmhTxnCRTfMNlug1UYo0QDCBRLxh4+KHdCyhzo+tpJaR7B0JPNSHputeCssN4KuJjk/hMFrR6R3dMOIIKKRuUPyELGKd+QWgUKI7a0ZVZlX8Q9bHOw+Ow9Yr1Xy3mKeX6leIVoDL8X4thORWW36lVZA+argFf87mQTqJ34L23m62jJlkrDJKqvmbwNUR9ifuZfoNwuwC0JVnkIDw0gUE0j9351kZY4dZ3gS0gszs6mkN7kE1b4coE+v3b5vTulw/Ba/OR6jYRgWwZSl9fr8cPWAIwdE9AzOvCc4e10WE0W7j0gPalxvBTrjTKrehkH25uCYJOLAM+DOnDgEbz7NH9AwJOoUNaMoS8gn2Z2R75BsSlghLVXbYp6k= X-Bogosity: Ham, tests=bogofilter, spamicity=0.001499, 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 Tue, Feb 11, 2025 at 5:08=E2=80=AFPM Waiman Long wr= ote: > diff --git a/mm/kasan/report.c b/mm/kasan/report.c > index 3fe77a360f1c..e1ee687966aa 100644 > --- a/mm/kasan/report.c > +++ b/mm/kasan/report.c > @@ -398,9 +398,20 @@ static void print_address_description(void *addr, u8= tag, > pr_err("\n"); > } > > - if (is_vmalloc_addr(addr)) { > - struct vm_struct *va =3D find_vm_area(addr); > + if (!is_vmalloc_addr(addr)) > + goto print_page; > > + /* > + * RT kernel cannot call find_vm_area() in atomic context. > + * For !RT kernel, prevent spinlock_t inside raw_spinlock_t warni= ng > + * by raising wait-type to WAIT_SLEEP. > + */ > + if (!IS_ENABLED(CONFIG_PREEMPT_RT)) { > + static DEFINE_WAIT_OVERRIDE_MAP(vmalloc_map, LD_WAIT_SLEE= P); > + struct vm_struct *va; > + > + lock_map_acquire_try(&vmalloc_map); > + va =3D find_vm_area(addr); Can we hide all this logic behind some function like kasan_find_vm_area() which would return NULL for -rt? > if (va) { > pr_err("The buggy address belongs to the virtual = mapping at\n" > " [%px, %px) created by:\n" > @@ -410,8 +421,13 @@ static void print_address_description(void *addr, u8= tag, > > page =3D vmalloc_to_page(addr); Or does vmalloc_to_page() secretly take some lock somewhere so we need to guard it with this 'vmalloc_map' too? So my suggestion above wouldn't be enough, if that's the case. > } > + lock_map_release(&vmalloc_map); > + } else { > + pr_err("The buggy address %px belongs to a vmalloc virtua= l mapping\n", > + addr); > } >