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To: kernel test robot Cc: oe-kbuild-all@lists.linux.dev, linux-kernel@vger.kernel.org, Andrew Morton , Linux Memory Management List Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: ABD3910000F X-Rspam-User: X-Rspamd-Server: rspam07 X-Stat-Signature: 59wbmaetmkywceq3w7jjwwmtdwg6fqrz X-HE-Tag: 1735465094-937288 X-HE-Meta: U2FsdGVkX18OaXQJPMmRYDMPUt3poCLdwAcPVVMf5oBhWKD2uQNcxj6zpSJi1u2GW/pbb7fCR8vtlXAMW6dvIF/YNBhd9lWLMmeLKRrRatUi6eLecQzt5iDKLYzDIeVNvPM1dkDnaCA8btSc6aREBCI5SAJp0OpMuetSdWfNQl2mDsaUOAcqdwJrNCpln1WsJEruJepXHCx7QR8qjv8+pf7X2cYsdXFYPr1G2nrfhIpbFBxtyQS0CREBnGpcnWzs159JzpQFtjHdoCsX1RULXoB71lhQSLzBaNYdvCUhKDHDOtlo+K0A9rGys3WagGFNgjaOUlKSX8OA4xDJkczw1GG26CBbXxzFjh14adWE/tda1DMYSDKMVuZETSc2sagYW57FskaHDRY2Up2TWZkV4X8Wn9WcrKHhmOfGCdMov2QOvSL5F6X+kLbkr9FGraL5+OvAh+Wr7ZK/A3lR9O4vRazPHpn6ZjHqf8mEhnVexRwsoHouRIBSiMqUwm5AVuigp8IYC5iFWm5lHVtqcJQMU0dzU7BE67wlaRZil/VJryBiFjDxDiEhPbXsJ7dlb32LZTVEhkF8YikjNPEdZJxWrLxy3dZMnAVwgAdvHpIh2M6EmNiXd/Krvz58Z6Wn+CvTRjIF5k4Mdal3UsBPRhbfKOgHVVWuMjj876195p3DYs7fJ0XiA+twF59GJOhLYpEf1m61ZnLJYTdRFpwu13B/uExNNe5ly9hKwZZ8Z/aIbgQYADIU039rcHOwJHUpgnRtmC/QMZFyYU9DQeCM6sIFhPWlet8cYmYkdvtT/1/yL6r8wZaLsgQDTA0nVp+jGy5ydDJYIzfpH8LLGRObkyEPY0/J/wIk528SoVkDxuOGUWDXE6AKUotRTQ1gQiPDneDnxMEVgnpuvkxiw7xvFBUPpccOeDjK1Jj4QGkE2+Mz8KEBAz3erBNd/LDoW+mlkZyBHhpW3SazMCzCQ0iAQ5R yPQKQISg v9FSBwjWG2uvJ4y+7YU3kGcrwShTtkUTDwTaQdlFzYcrRlXIu1N4+1V4uleZwt1mmWCHCczY/XkUDI7uxJzI95XORU5+jzb4bbwJTukkG3PVyd46k3L00V5Z5/WeaQkH7uWiN6eEqVXaWybd65T+1sRDS/uHaQ66FRZBdOBOh05SgLt3z3J52uW1UBXqeD622JRXH9xJl/6YdKyDcrVHm9A9la9eR0pisfRP7WhaXcyVZbLm2mzA5h4p86/9HM1vD97jqv3Q2f6i0qei/Xx6AKupb/jgPuQO/6Y5G+Px9RCwSncSL7FaO2roOYnttTYPlKwdjwNgGvWp0wDpWutTSe5y0numH7WiShHM6KedXqHPuAYHZTMhnSWJokUC0wKMEj3UxegP2gvVK/uWOze2TncPP0mWwTapen0vkpUBA2OkkmA1AUeIVnfUj44Q6f1lYyLFNYKqs/A0SLJFISvvicgdxXK0WUPsHbBfJv1ANr2oaivQ= 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, Dec 29, 2024 at 10:00=E2=80=AFAM kernel test robot = wrote: > > tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.gi= t master > head: 059dd502b263d8a4e2a84809cf1068d6a3905e6f > commit: 28e98022b31efdb8f1ba310d938cd9b97ededfe4 mm/list_lru: simplify re= parenting and initial allocation > date: 7 weeks ago > config: i386-randconfig-054-20241229 (https://download.01.org/0day-ci/arc= hive/20241229/202412290924.UTP7GH2Z-lkp@intel.com/config) > compiler: gcc-12 (Debian 12.2.0-14) 12.2.0 > > If you fix the issue in a separate patch/commit (i.e. not just a new vers= ion of > the same patch/commit), kindly add following tags > | Reported-by: kernel test robot > | Closes: https://lore.kernel.org/oe-kbuild-all/202412290924.UTP7GH2Z-lkp= @intel.com/ > > cocci warnings: (new ones prefixed by >>) > >> mm/list_lru.c:514:3-8: WARNING: NULL check before some freeing functio= ns is not needed. > > vim +514 mm/list_lru.c > > 470 > 471 int memcg_list_lru_alloc(struct mem_cgroup *memcg, struct list_lr= u *lru, > 472 gfp_t gfp) > 473 { > 474 unsigned long flags; > 475 struct list_lru_memcg *mlru; > 476 struct mem_cgroup *pos, *parent; > 477 XA_STATE(xas, &lru->xa, 0); > 478 > 479 if (!list_lru_memcg_aware(lru) || memcg_list_lru_allocate= d(memcg, lru)) > 480 return 0; > 481 > 482 gfp &=3D GFP_RECLAIM_MASK; > 483 /* > 484 * Because the list_lru can be reparented to the parent c= group's > 485 * list_lru, we should make sure that this cgroup and all= its > 486 * ancestors have allocated list_lru_memcg. > 487 */ > 488 do { > 489 /* > 490 * Keep finding the farest parent that wasn't pop= ulated > 491 * until found memcg itself. > 492 */ > 493 pos =3D memcg; > 494 parent =3D parent_mem_cgroup(pos); > 495 while (!memcg_list_lru_allocated(parent, lru)) { > 496 pos =3D parent; > 497 parent =3D parent_mem_cgroup(pos); > 498 } > 499 > 500 mlru =3D memcg_init_list_lru_one(gfp); > 501 if (!mlru) > 502 return -ENOMEM; > 503 xas_set(&xas, pos->kmemcg_id); > 504 do { > 505 xas_lock_irqsave(&xas, flags); > 506 if (!xas_load(&xas) && !css_is_dying(&pos= ->css)) { > 507 xas_store(&xas, mlru); > 508 if (!xas_error(&xas)) > 509 mlru =3D NULL; > 510 } > 511 xas_unlock_irqrestore(&xas, flags); > 512 } while (xas_nomem(&xas, gfp)); > 513 if (mlru) > > 514 kfree(mlru); Hmm, does it need a fix? mlru here is most likely always NULL, so in most cases this should save a function call, a really micro optimization. Perhaps a "if (unlikely(mlru))" is better, and silence the bot? > 515 } while (pos !=3D memcg && !css_is_dying(&pos->css)); > 516 > 517 return xas_error(&xas); > 518 } > 519 #else > 520 static inline void memcg_init_list_lru(struct list_lru *lru, bool= memcg_aware) > 521 { > 522 } > 523 > > -- > 0-DAY CI Kernel Test Service > https://github.com/intel/lkp-tests/wiki >