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Fri, 27 Feb 2026 00:21:46 -0800 (PST) Received: from tigerii.tok.corp.google.com ([2a00:79e0:2031:6:280f:e47e:6718:7698]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2adfb69fa4fsm48796025ad.45.2026.02.27.00.21.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 27 Feb 2026 00:21:45 -0800 (PST) From: Sergey Senozhatsky To: Andrew Morton , Minchan Kim Cc: linux-kernel@vger.kernel.org, linux-block@vger.kernel.org, linux-mm@kvack.org, Brian Geffon , Sergey Senozhatsky Subject: [PATCH 1/5] zram: do not autocorrect bad recompression parameters Date: Fri, 27 Feb 2026 17:21:07 +0900 Message-ID: <8a5d53d19a8dbd51d7d81d153676895163e0735e.1772180459.git.senozhatsky@chromium.org> X-Mailer: git-send-email 2.53.0.473.g4a7958ca14-goog MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspamd-Server: rspam12 X-Rspamd-Queue-Id: C22204000A X-Stat-Signature: qesnnfpdcsispk8on8kggh3c8sa5yhdk X-Rspam-User: X-HE-Tag: 1772180507-963549 X-HE-Meta: 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 eJeJ8pGJ 4i0f5mw8Ot+XbV1FGBBQdc2tmAy8I4ff694uWHvQ10rRPa9PzaKiFpMxzyeYLHX+ifJaJY5NxKS1AsnbIuNH15sMNgDW+O2P2IAmR9ybeOm/OCeEidWfFkDXI3EvbUG2AFWR1oH/Dxvu1X08b37x0TszWZ4LvD+DfLSY/hx2f0qMJa5bYhTR5tF5H0pDLmvv1kvuobf1e9FiiOSol9cYYs5ffoxvQ+qaoXdWNvRJjzHD48CyNV0eFEmE+ygXBBjpyEGUMGxn8LmfrBdmJUuMO82P+FJVzDiyohHQ5g0k39Rdzd/I4ixO83xw2n9IzlKO52cd7+bO8v5CU8Ok= Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Do not silently autocorrect bad recompression priority parameter value and just error out. Suggested-by: Minchan Kim Signed-off-by: Sergey Senozhatsky --- drivers/block/zram/zram_drv.c | 17 ++++++++--------- 1 file changed, 8 insertions(+), 9 deletions(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 4eaec24a23fe..53e0bbf9d6ec 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -2524,19 +2524,16 @@ static ssize_t recompress_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t len) { + u32 prio = ZRAM_SECONDARY_COMP, prio_max = ZRAM_MAX_COMPS; struct zram *zram = dev_to_zram(dev); char *args, *param, *val, *algo = NULL; u64 num_recomp_pages = ULLONG_MAX; struct zram_pp_ctl *ctl = NULL; struct zram_pp_slot *pps; u32 mode = 0, threshold = 0; - u32 prio, prio_max; struct page *page = NULL; ssize_t ret; - prio = ZRAM_SECONDARY_COMP; - prio_max = zram->num_active_comps; - args = skip_spaces(buf); while (*args) { args = next_arg(args, ¶m, &val); @@ -2586,10 +2583,7 @@ static ssize_t recompress_store(struct device *dev, if (ret) return ret; - if (prio == ZRAM_PRIMARY_COMP) - prio = ZRAM_SECONDARY_COMP; - - prio_max = prio + 1; + prio_max = min(prio + 1, ZRAM_MAX_COMPS); continue; } } @@ -2609,7 +2603,7 @@ static ssize_t recompress_store(struct device *dev, continue; if (!strcmp(zram->comp_algs[prio], algo)) { - prio_max = prio + 1; + prio_max = min(prio + 1, ZRAM_MAX_COMPS); found = true; break; } @@ -2627,6 +2621,11 @@ static ssize_t recompress_store(struct device *dev, goto out; } + if (prio < ZRAM_SECONDARY_COMP || prio >= ZRAM_MAX_COMPS) { + ret = -EINVAL; + goto out; + } + page = alloc_page(GFP_KERNEL); if (!page) { ret = -ENOMEM; -- 2.53.0.473.g4a7958ca14-goog