]> git.ipfire.org Git - thirdparty/kernel/stable.git/commit
x86/fpu: Delay instruction pointer fixup until after warning
authorDave Hansen <dave.hansen@linux.intel.com>
Wed, 13 Aug 2025 15:59:47 +0000 (11:59 -0400)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Thu, 28 Aug 2025 14:24:31 +0000 (16:24 +0200)
commit1b2b7e9da01ea884b8b790b5fc5975abc82d2590
tree630f52c6d11b5f4a93cf63a51e9d3258df737d48
parent6550b2bef095d0dd2d2c8390d2ea4c3837028833
x86/fpu: Delay instruction pointer fixup until after warning

[ Upstream commit 1cec9ac2d071cfd2da562241aab0ef701355762a ]

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 the
non-FPU-related instruction is #GP'ing.

Do not fix up RIP until after printing the warning. Do this by using
the more generic and standard ex_handler_default().

Fixes: d5c8028b4788 ("x86/fpu: Reinitialize FPU registers if restoring FPU state fails")
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Chao Gao <chao.gao@intel.com>
Acked-by: Alison Schofield <alison.schofield@intel.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc:stable@vger.kernel.org
Link: https://lore.kernel.org/all/20250624210148.97126F9E%40davehans-spike.ostc.intel.com
[ Replace fpu_reset_from_exception_fixup() with __restore_fpregs_from_fpstate() ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
arch/x86/mm/extable.c