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X-MS-Exchange-AntiSpam-MessageData: =?us-ascii?Q?8IfF5fLSOEnhfapYEleBxPInESTnO/kLluXJgDLni0sQ8lp8bAd6O2BY2lHu?= =?us-ascii?Q?oSPmax0JresdNMkZX2Z2Ee7n6BXNfarOlIzmNpAJE1wRNVl5YS1Nq6IIThpr?= =?us-ascii?Q?Wrml6yJZ4K7BE6dlSwk+WsfymcE/Q1TEUmYtQogezlwgkXJab5zP4S3IYdz1?= =?us-ascii?Q?lK+fkNnjzy+rm+brV/l0dsaJGBmbQnwVSV9G1sPvlKw+myjELlQajNYW7n+v?= =?us-ascii?Q?dcFpEL9WBN73bbLrmlYxdNoJNBgihU96p9c8m1qycjazQTpbC4KeFr4hKooP?= =?us-ascii?Q?u0Mi6457MwA1cVe27aGCbIb/7EZZH9yjCvoEEkDNyOvlgmdGsJdUQquXK2lY?= =?us-ascii?Q?Z4xyiy4JRr2pPjbJYzClOq1LS4TWcu56CAmGaXt6IBnIa2VaWPHMh6hyI3X4?= =?us-ascii?Q?l0pWx42oQSf/4Gqtma/z0svoeWzmb46FyPoDhavjRG64QsXzilQSuT+a9pUi?= =?us-ascii?Q?eNsvCRKiot7MXzYbwmZg1inz0KJh612GxgQHKHTOGOrEMgRFCDRmsqTsn/2g?= =?us-ascii?Q?X4qYo4zOR13IO3Ryk3gO+jVS4CbyN8SwlMKpZQvuoCsvDIpNBRsPP7S4DmGj?= =?us-ascii?Q?W6Q/sLp8X7+x8sjJLn0/RmlqAQWQhqotX7KSqyEDbPj0h+gjG3fgm0tAyWOq?= =?us-ascii?Q?cOiZKwnXVgPfMfou7TKfT6w21o5cstQgs1Av3rO3adWycfcEsFQAJaYL1DSo?= =?us-ascii?Q?TGjLLCvbe/naHwNqZ4SIfAZ7SB0xsmpboEi1oTqE22N1udVLDalmolEglHLi?= =?us-ascii?Q?bWqBcJMgi7iNhXJOeyOhD273DcKDfdVl1clioRe85ksw+h/boHk0icShLsbZ?= =?us-ascii?Q?lBKBGyEJwkrYmv0x5BNkS/vqJROWe60eY3e5p7FlAICn9wRaMb3us/aJBwFZ?= =?us-ascii?Q?Ci5rQUmbdVFM0PkipjCuozkKYl77W4sI6Z88kbx2zH7jUqAcK/TbLm2S+AFl?= =?us-ascii?Q?QREnvqBWrf969aY8jMeT08dl8jXCOXkv7GJYB0lWa1TG6Ize2M425QRRNzDD?= =?us-ascii?Q?flwjLNtml51Q7mti3xexZYA4XYZqVOOW7qowjGkzI6KzmhnuTdk51XPX9YXG?= =?us-ascii?Q?0hUsY/w1snToxKnt5iYE/6A6XUMAVF0AFH5sVVnDRwpFCS0O3ZGIoF96QMN9?= =?us-ascii?Q?nnx2L/RB1k5wUlk4OKyV6OAaA0DJhguTbXUcGa2u+Q4v3x8KZ2dFgidmAGtA?= =?us-ascii?Q?/QTmp5/MAm0sYbHotWVy4VSscDmvQRfgJ2IOeCDLrGDVdjOsRWMu/Egri4Is?= =?us-ascii?Q?zpdMY8uTD0f6tm5aV8ygXV/4Bbuc7jRQrKUgVyOH2/CaMDaMXmOYoVUDW5g4?= =?us-ascii?Q?rmw3FOiGJR4Izy+ZvL9vOezn?= X-OriginatorOrg: windriver.com X-MS-Exchange-CrossTenant-Network-Message-Id: 779c8db8-7902-4f6e-3cdd-08d902b4924b X-MS-Exchange-CrossTenant-AuthSource: DM6PR11MB4545.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Apr 2021 21:54:42.3798 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 8ddb2873-a1ad-4a18-ae4e-4644631433be X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: Qx7cQdn9pECrppenEWdqrRLLRR9li6tdDJ6VUPkhbk/OMefXfh0hdqlzawIrAD4r6qLB6H9d/q4LbuNRe3FXTd+DztbpvhX1nXy8dbhHtCs= X-MS-Exchange-Transport-CrossTenantHeadersStamped: DM5PR1101MB2331 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org After commit 3662daf02350 ("sched/isolation: Allow "isolcpus=" to skip unknown sub-parameters") the isolcpus= string is walked to skip over what might be any future flag comma separated additions. However, there is a logic error, and so as can clearly be seen below, it will ignore its own arg len and search to the end of the bootarg string. $ dmesg|grep isol Command line: BOOT_IMAGE=/boot/bzImage isolcpus=xyz pleasedontparseme=1 root=/dev/sda1 ro isolcpus: Skipped unknown flag xyz isolcpus: Invalid flag pleasedontparseme=1 root=/dev/sda1 ro This happens because the flag "skip" code does an unconditional increment, which skips over the '\0' check the loop body looks for. If the isolcpus= happens to be the last bootarg, then you'd never notice? So we only increment if the skipped flag is followed by a comma, as per what the existing "continue" flag matching code does. Note that isolcpus= was declared deprecated as of v4.15 (b0d40d2b22fe), so we might want to revisit that if we are trying to future-proof it as recently as a year ago for as yet unseen new flags. Cc: Peter Xu Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Peter Zijlstra Cc: Frederic Weisbecker Fixes: 3662daf02350 ("sched/isolation: Allow "isolcpus=" to skip unknown sub-parameters") Signed-off-by: Paul Gortmaker diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c index 5a6ea03f9882..9652dba7e938 100644 --- a/kernel/sched/isolation.c +++ b/kernel/sched/isolation.c @@ -188,7 +188,8 @@ static int __init housekeeping_isolcpus_setup(char *str) } pr_info("isolcpus: Skipped unknown flag %.*s\n", len, par); - str++; + if (str[1] == ',') /* above continue; match on "flag," */ + str++; } /* Default behaviour for isolcpus without flags */ -- 2.25.1