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Wed, 18 Jun 2025 19:51:23 +0000 Date: Wed, 18 Jun 2025 12:51:13 -0700 From: Alison Schofield To: Dave Hansen CC: , , , , , "Chang S. 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?IUoL/V88jNlmxt9Xyg3aq0Vz+/IUA8ILwF4ptWyV360bOJQ3N5HGu93cOfsl?= =?us-ascii?Q?SfeiRvGJ4ptggJfF5MS/1icquZXOO7YJzddS2gGaWU564FKfv+zna0ucRSQA?= =?us-ascii?Q?0bt0GSG4Ryy8jUo9371ku5UyH+u1hXlTLCJlXmbqJzOp0FlEepFzxPKTjgYO?= =?us-ascii?Q?edpjk6INAfVkzvDHXph6EcEUS94kNVkek8EoE7MxDT/Lj/xT/NDWeBaO/nfn?= =?us-ascii?Q?g48+NEmA8XBeoM2BFnBbBp2RuCjiKABPBsupoSrTqdYKccqMF9Nb9mc+bdl2?= =?us-ascii?Q?CfDHplr6nAURJlkP5YHJYs0PQJKKIbU+OrS3spLt+am3NcuaAgUGFnUwMTb+?= =?us-ascii?Q?Ua7PTjcd+aAafNhNavcb9adPdu+kGgnyIRZaABN9NfXK8ZdJzy6la12CniVv?= =?us-ascii?Q?jIr6v8wd8saLxxd4lb8FsR+IcsHH0jWyr9vnAmXkfiO0hfXYJuJneMIYeWdz?= =?us-ascii?Q?qO9e94BIMebV//t09iW8KNwA0KvyuAANsLYSH4Ah17enp0Dh9aYIFnv5JW6E?= =?us-ascii?Q?5PwPT4zDM5CBervgutRpOGtC7aCdYU5FQFmYbrC/ny/FUkWCGucQIaBkQtyk?= =?us-ascii?Q?YZcJIpJHodZwWzaFZ9PhIs53Tm8B33pzmpqY/eJw1jLmdPz7qh+hxapFol6P?= =?us-ascii?Q?LkLwpyCUeyJB0Ve6Lq8DpFfSIsUwqsQa+9sOt53XzqySAA995H6ofLv/MP+H?= =?us-ascii?Q?9OXfcrmNrWCNJQw+BRW7lSdrTmI67WxXMQfPzjsCoQvtmzw53Ea+kFyWoSFn?= =?us-ascii?Q?osDzEwBsiV55XBedZe6+4FfTejWBxIkBShogmUMYQuFNeZrKKVKQ+uK0Dke6?= =?us-ascii?Q?MdsKJVVFnG9Sx3GvQFjxgtlgpGCuB4cD3wKlmgrNcj9t4FT7I+Hrs2BwZbSX?= =?us-ascii?Q?9aptXP7Hgm1bI5xrHm7hubl6PiAq5vbJkPhf3icIrml1K7iFFpdTWP7pWn1k?= =?us-ascii?Q?yI++FltpQwHMvwIntqiwpCT8tomU4GJ6INis4OUG/p9VUn8Mh4/y6o03+BKz?= =?us-ascii?Q?UZeoNKjQYO9SP1sTLN492EPZc8RnooQHYsIZVevGlff1+OHHOpwTasjI0mxP?= =?us-ascii?Q?EyoRNxIderH4f1qU4LxrIUxAR5L+T5Rt0CLnnjvOk3/JcXsyFTtGtg4n192t?= =?us-ascii?Q?/mxiM42Ik9GsjgJHkhGEvkH2ZvIayfAH8GFg4jmyZebs2W81s8f8JC2NKzra?= =?us-ascii?Q?h/FJv3UB4moy3LoSFzqH4Ie2X+Xk1GXm4DYkfygTOkZgrsYkXzj2qbAeJrJB?= =?us-ascii?Q?feih1FVZp4B/npcLNBdq9lGfJDnzMV97FGRGT4wnwW3l0ItqAiu0YehgcbD4?= =?us-ascii?Q?0JhgVvCPl4yat+WPnFS9WlgdFizMRVCAwfZ+gPtOWXWoNB+pY+KumSs2BZPh?= =?us-ascii?Q?VGM0dMmrJQ3oHsmmI89MhizxN2XLf+dgf5TxaXK8f6jLCWg9NnqO0NPiE6G+?= =?us-ascii?Q?j9BcljX4bHcFE/N9kb5JTRuFrUqOw6xgdo2QZSR0b1OIRew3Nhz5Iyvz49HR?= =?us-ascii?Q?i8BcnzGh1r0H7cw59lma/1PM9TbFv6a28ajfrSjRZOlXB4TyoF7fIL2+Q1uI?= =?us-ascii?Q?BIumWS1DEr0hvpHrA7QHLTRNtwpYbAikC38r3kLGz5T5c4uy0sgE21NdHMD+?= =?us-ascii?Q?ng=3D=3D?= X-MS-Exchange-CrossTenant-Network-Message-Id: e975f829-c38b-4a15-6d0f-08ddaea18113 X-MS-Exchange-CrossTenant-AuthSource: SA1PR11MB8794.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Jun 2025 19:51:23.8965 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: OXG4o3fEFE6jntihfp90VsM7Pk5CVKgVOM4dBpOE/EaGv2vhc74LYv58YUmThScKUeZOHuYUMTgOvq6WODNieBZchWlE3juphaxBprQvIxY= X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR11MB7879 X-OriginatorOrg: intel.com On Wed, Jun 18, 2025 at 12:33:13PM -0700, Dave Hansen wrote: > > From: Dave Hansen In the subject line: s/after after/after > > Right now, if XRSTOR fails a console message like this is be printed: > > Bad FPU state detected at restore_fpregs_from_fpstate+0x9a/0x170, reinitializing FPU registers. > > However, the text location (...+0x9a in this case) is the instruction > *AFTER* the XRSTOR. The highlighted instruction in the "Code:" dump > also points one instruction late. > > The reason is that the "fixup" moves RIP up to pass the bad XRSTOR > and keep on running after returning from the #GP handler. But it > does this fixup before warning. > > The resulting warning output is nonsensical because it looks like > e non-FPU-related instruction is #GP'ing. s/e/the > > Do not fix up RIP until after printing the warning. How was this found and how is the change verified? ie. do we have a mechanism for hitting this path easily? With the grammar cleanups, Acked-by: Alison Schofield > > Signed-off-by: Dave Hansen > Fixes: d5c8028b4788 ("x86/fpu: Reinitialize FPU registers if restoring FPU state fails") > Cc: stable@vger.kernel.org > Cc: Eric Biggers > Cc: Rik van Riel > Cc: Borislav Petkov > Cc: Chang S. Bae > --- > > b/arch/x86/mm/extable.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff -puN arch/x86/mm/extable.c~fixup-fpu-gp-ip-later arch/x86/mm/extable.c > --- a/arch/x86/mm/extable.c~fixup-fpu-gp-ip-later 2025-06-18 12:21:30.231719499 -0700 > +++ b/arch/x86/mm/extable.c 2025-06-18 12:25:53.979954060 -0700 > @@ -122,11 +122,11 @@ static bool ex_handler_sgx(const struct > static bool ex_handler_fprestore(const struct exception_table_entry *fixup, > struct pt_regs *regs) > { > - regs->ip = ex_fixup_addr(fixup); > - > WARN_ONCE(1, "Bad FPU state detected at %pB, reinitializing FPU registers.", > (void *)instruction_pointer(regs)); > > + regs->ip = ex_fixup_addr(fixup); > + > fpu_reset_from_exception_fixup(); > return true; > } > _