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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?bmkxbVo1cDZzWFZMTnp1VlN2Uk93SWI4MDZSYW9QaWlMUFAwSTZoS0l6SHFu?= =?utf-8?B?YUNxMDZNakUxY3FXbEtGQlJBYzVkMEtKbkF0NzBXV0RrQnZTY3pyOUwxMHVD?= =?utf-8?B?T1g0WVUrNnAxMTA5bzVxMVZsdGlGS0Z4dmk3cjI3SGljWm5LdmJ3c3drYXha?= =?utf-8?B?SXdyRjZEamgxbW4xUnFzQlVaUlplSVJyUEI2T1QwaWV6TldlNnVSTmtLUlcz?= =?utf-8?B?VnVDTXBhQUpKZjdwTlZPd2QyZlA2TGpiWERLODI1SWViMitMVVkveUVUbXVw?= =?utf-8?B?Z2JzTDc4eFUxR2wrTHNlTHR1d1VqNmpCTzg1TUx6L1I0bHBhSTlhdlFBYk5p?= =?utf-8?B?emM3Wm16cllna0o4NkxaV2N0b0N2WVp2NlU3RnorOFdNNHJNTXlzTVkwYmxK?= =?utf-8?B?OGlYdlNyNVpOTFVmRmdmY0ZaMkUxcTRZMzREc1ZhM3JMUHVKTnNrQndUWWN3?= =?utf-8?B?RjJTTzg2OUJqQ2g4ekFETjlSM2x0SFNkckdkYUFvbzd0azQ2V0o1VVUwTzNB?= =?utf-8?B?cGNmQTdmOVhmRkhjbVpJT3lWV3B0VnYrRFFWUDRwMlFvWVBZRVJiRlpEcm1n?= =?utf-8?B?U2ZvTEFESmVIRTI0VmVFMHVaekNVU2RSNkhyZU13SXk0cXJ5R3dqOFBNc1JW?= =?utf-8?B?QXhQN1UzSW1FRE5BVm1Da1FMcWhSQTA5eGY3WEx2UHRCT0hiY0VLTFhpSlY4?= =?utf-8?B?UzNIZHgzaitJeFFUWXBRK2o5MnVjelN5TVU2aHFlZlQzSVA0TnZXakpXbDkr?= =?utf-8?B?M3VyNUxsbVphZG9vUU8zTXkyL3pxMVRia1FIM1ZlRlNUMFpoNTg5WjlBcnRv?= =?utf-8?B?cm5DdllCNTI3bTBrV0FrMmRYVEZ3N1o0bFFXenBKaUpCWERwN3cvZHFQdDFi?= =?utf-8?B?TG0rRHBHSmxCNXcvaHNHbDJqb1Z4T3F5Y01tWTZPaVcxUEw5dGhVRlBxdWlJ?= =?utf-8?B?WjBCQ1dnclA1dkxtd1I1MWMvQnB6WGk0Ti9qd3c4dkJsOUJxSEl3dFhZeWZV?= =?utf-8?B?Q092MG9LdXoxdXM2ZmlINVV1NTNrelFOR1ZVYzh4S3J3dkw3OGdkMHMrTG9w?= =?utf-8?B?R3psSEkvMHdQQjY3UEhFSUZSWnB1YXgyOXcwTGEwUi9JSjhlUHFyOXBZSHND?= =?utf-8?B?SzMxZVE5R0RCYnhwU2xVZjlzMjlyWE8rRVdFT0pJWjF0RXRKRmp4bmJaNC9K?= =?utf-8?B?OG03dmgzeU85UzFod2FNTGkrc3JPcG4rSEwyVXJ5NW8rZ08yRXFuRVRZUEdW?= =?utf-8?B?V2x2THZjMXRBbGRNeUNLdlpYWkxMT0pZZU1Sc0hodDF6UjJnQVcxMkxsbzRy?= =?utf-8?B?TXdFRm5DaW1FM05tbHdsRFNOSmFqZXlnN0JCN0VwNkZZeUZSTUEvM2gzc3Q2?= =?utf-8?B?ZFJ6MFZQNGkwL29yT0JydkZPR3JJVzlDbWQ0OStsbjJEL2F3V2JPNUxIK1Mr?= =?utf-8?B?V0QzbGtvQ0ZHY1hGcGVxWHBHclJtbzFXV0IvZGlhWTNGQ3o5bHdHUlFLR2J0?= =?utf-8?B?TC9zeVRDSU84UHowZ2taYWJOVm1pYXdpb1AyelQ2aC81WitkZUw5TnJSTkJj?= =?utf-8?B?UHF4V3hpMEdUL0VkSUdwVkUvRkdhTndwc0xCZjlGM2xpOXl3UEd4OGh4TklI?= =?utf-8?B?RVR0WHBQOGlmZGRLck9XQXdJRWhkUlJweHZnd0VRUXg3V0lNWC95SWtQQ2JJ?= =?utf-8?B?OURiQ3FIeElXcGlIMHhjMEx6ckgvbC9rNlIyVXdoOU1kQzUxOXZyNlIxakxV?= =?utf-8?Q?x+N+QIi9DMeUITMflxKyPJjI5USvnnfL8cQorsn?= X-MS-Exchange-CrossTenant-Network-Message-Id: 9700348b-18aa-40e4-91d4-08d979dec9eb X-MS-Exchange-CrossTenant-AuthSource: BYAPR03MB3623.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 17 Sep 2021 13:26:43.0133 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 335836de-42ef-43a2-b145-348c2ee9ca5b X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: wiW4EGTRfDi68n41ne99Dpwxn7fAHoIAOP/ZzyyodP/58nP0j5wVTbPm3vMhPwvTLQpe1aB5KrH+J1ceyAmF5AxQ9yuZHHKQBRwOdKikQiA= X-MS-Exchange-Transport-CrossTenantHeadersStamped: BYAPR03MB3799 X-OriginatorOrg: citrix.com On 17/09/2021 13:58, Jan Beulich wrote: > On 17.09.2021 10:45, Andrew Cooper wrote: >> --- a/xen/common/trace.c >> +++ b/xen/common/trace.c >> @@ -686,22 +686,21 @@ void __trace_var(u32 event, bool_t cycles, unsigne= d int extra, >> unsigned long flags; >> u32 bytes_to_tail, bytes_to_wrap; >> unsigned int rec_size, total_size; >> - unsigned int extra_word; >> bool_t started_below_highwater; >> =20 >> if( !tb_init_done ) >> return; >> =20 >> - /* Convert byte count into word count, rounding up */ >> - extra_word =3D (extra / sizeof(u32)); >> - if ( (extra % sizeof(u32)) !=3D 0 ) >> - extra_word++; >> - =20 >> - ASSERT(extra_word <=3D TRACE_EXTRA_MAX); >> - extra_word =3D min_t(int, extra_word, TRACE_EXTRA_MAX); >> - >> - /* Round size up to nearest word */ >> - extra =3D extra_word * sizeof(u32); >> + /* >> + * Trace records require extra data which is an exact multiple of >> + * uint32_t. Reject out-of-spec records. Any failure here is an e= rror in >> + * the caller. >> + */ > Hmm, is "require" accurate? In terms of "what will go wrong if this condition is violated", yes. > They may very well come without extra data > afaics. 0 is fine, and used by plenty of records, and also permitted by the filtering logic. > >> + if ( extra % sizeof(uint32_t) || >> + extra / sizeof(uint32_t) > TRACE_EXTRA_MAX ) >> + return printk_once(XENLOG_WARNING >> + "Trace event %#x bad size %u, discarding\n", >> + event, extra); > Any HVM guest looks to be able to trivially trigger this log message > (via HVMOP_xentrace), thus pointing out an issue in a guest and hiding > any other Xen related output. I'd like to suggest to adjust that call > site in prereq patch (I'm not overly fussed which of the two relatively > obvious ways). > > Further sched/rt.c:burn_budget() has a bool field last in a packed > struct, yielding a sizeof() that's not a multiple of 4. All the uses of > __packed there look at best suspicious anyway. Ugh - I checked the __trace_var() users, but not trace_var().=C2=A0 Luckily= , there are far fewer of the latter. HVMOP_xentrace has no business being a hypercall in the first place.=C2=A0 That can be fixed by also enforcing the multiple-of-4 requirement. But yes - burn_budget() needs fixing in this patch too, taking it from a theoretical to real problem. ~Andrew