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b=ohOY26JzrJ84xK6XyL8AqFmyDkTo9LE/qIAUO8G0H5ib8aLYkqsqgg4iN4HhwC9A8 dSCzzo+xsEtHkc7jQ89GIDOau3gUAOxUVGwQECL+G4gWuQ39gpN4wNlvTaJw6S4eCK 6cauPx1p8PM4trko8Ybe0AOqRbLrch7ro1uFZaESGAkC4yrEtka4JS/mJQb+cz9OBs VyLO4ZxrNZu41kCGli0yUgqOe5BHni16a6XnX7cGom+wTldN+siH/m/WQ7cBSSnvFu p+6l9II2GAjI69e6mCttfNJniZ2cFHw8I1y5eFA3aZdR5kW4p5ErP9PalcG5xHtwHP +JMxQvcfiW7bg== Content-Type: multipart/mixed; boundary="===============1148049922040317406==" MIME-Version: 1.0 Message-Id: In-Reply-To: <20251219015750.23732-5-roman.gushchin@linux.dev> References: <20251219015750.23732-5-roman.gushchin@linux.dev> Subject: Re: [PATCH bpf-next v1 4/6] mm: introduce BPF kfuncs to access memcg statistics and events From: bot+bpf-ci@kernel.org To: roman.gushchin@linux.dev,bpf@vger.kernel.org,linux-mm@kvack.org,linux-kernel@vger.kernel.org Cc: inwardvessel@gmail.com,ast@kernel.org,daniel@iogearbox.net,shakeel.butt@linux.dev,mhocko@kernel.org,hannes@cmpxchg.org,roman.gushchin@linux.dev,mhocko@suse.com,ast@kernel.org,andrii@kernel.org,daniel@iogearbox.net,martin.lau@kernel.org,eddyz87@gmail.com,yonghong.song@linux.dev,clm@meta.com,ihor.solodrai@linux.dev Date: Fri, 19 Dec 2025 02:15:11 +0000 (UTC) X-Rspamd-Server: rspam02 X-Stat-Signature: bwx67pjr7csa4tkd4zai9kk19p3t367n X-Rspam-User: X-Rspamd-Queue-Id: 2586B14000A X-HE-Tag: 1766110512-803010 X-HE-Meta: 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 zRiHSUiV RObwzhlYnD6KKPwnmYG3x0qOaN00sT0hsVVjjvWVJhmVoz0JrsWUo4fHoAxej/8bIo4bzUNekgj6UKT3f7d9Z8VJEtIDRFxgq8oFihD0zLhOKGtmML1a7SiqFZs8v+MmcS3EWC8aS0vFzKjL9OyeUSgmB0jiRhgTsnbc4Lc8QNikFswQaEvSPtAnXQfY4ag7DgDhrvQUFxXtWD85TEvCZ7GeEOJlODtJN32PHbBGitqlgSMp3bFqzQXsylehXU+L7DdV+94TA6b5erkWDtJZK91WVePLpR8dTNKBf46BRSnDzUF3hldHLl460UAhaug6FMHJXoMC9GpXY904rb9emaKF6jDVVUKGciZHZSPacnxddf4G+BUPMK8OXxNSEHsFV9C5fG9GSLAWYs1DbZLYXsLS+tCcQwS/NLLSGiI6/Mz7o2tM= 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: --===============1148049922040317406== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit > diff --git a/mm/bpf_memcontrol.c b/mm/bpf_memcontrol.c > index 6d0d73bf0dd1..4d9d7d909f6c 100644 > --- a/mm/bpf_memcontrol.c > +++ b/mm/bpf_memcontrol.c [ ... ] > +/** > + * bpf_mem_cgroup_vm_events - Read memory cgroup's vm event counter > + * @memcg: memory cgroup > + * @event: event id > + * > + * Allows to read memory cgroup event counters. > + */ > +__bpf_kfunc unsigned long bpf_mem_cgroup_vm_events(struct mem_cgroup *memcg, > + enum vm_event_item event) > +{ > + return memcg_events(memcg, event); > +} Should bpf_mem_cgroup_vm_events() validate the event parameter before passing it to memcg_events()? The call chain is: bpf_mem_cgroup_vm_events() -> memcg_events() -> memcg_events_index() And memcg_events_index() does: return mem_cgroup_events_index[idx]; where mem_cgroup_events_index is an array of size NR_VM_EVENT_ITEMS. If a BPF program passes event >= NR_VM_EVENT_ITEMS, this would be an out-of-bounds array read. The sister function bpf_mem_cgroup_page_state() below validates its idx parameter before calling its callee: > +/** > + * bpf_mem_cgroup_page_state - Read memory cgroup's page state counter > + * @memcg: memory cgroup > + * @idx: counter idx > + * > + * Allows to read memory cgroup statistics. The output is in bytes. > + */ > +__bpf_kfunc unsigned long bpf_mem_cgroup_page_state(struct mem_cgroup *memcg, int idx) > +{ > + if (idx < 0 || idx >= MEMCG_NR_STAT) > + return (unsigned long)-1; > + > + return memcg_page_state_output(memcg, idx); > +} Should bpf_mem_cgroup_vm_events() have a similar bounds check, perhaps: if (event >= NR_VM_EVENT_ITEMS) return (unsigned long)-1; before calling memcg_events()? [ ... ] --- AI reviewed your patch. Please fix the bug or email reply why it's not a bug. See: https://github.com/kernel-patches/vmtest/blob/master/ci/claude/README.md CI run summary: https://github.com/kernel-patches/bpf/actions/runs/20357445962 --===============1148049922040317406==--