* [PATCH] x86/percpu: Return correct variable from current_top_of_stack()
@ 2023-10-24 14:28 Uros Bizjak
2023-10-24 15:56 ` Borislav Petkov
2023-10-24 16:41 ` [tip: x86/percpu] " tip-bot2 for Uros Bizjak
0 siblings, 2 replies; 4+ messages in thread
From: Uros Bizjak @ 2023-10-24 14:28 UTC (permalink / raw)
To: x86, linux-kernel
Cc: Uros Bizjak, Andy Lutomirski, Brian Gerst, Denys Vlasenko,
Ingo Molnar, H . Peter Anvin, Linus Torvalds, Peter Zijlstra,
Thomas Gleixner, Josh Poimboeuf
current_top_of_stack() should return variable from _seg_gs
qualified named address space when CONFIG_USE_X86_SEG_SUPPORT
is enbled.
Fixes: ed2f752e0e0a ("x86/percpu: Introduce const-qualified const_pcpu_hot to micro-optimize code generation")
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
---
arch/x86/include/asm/processor.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index a807025a4dee..4b130d894cb6 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -534,7 +534,7 @@ static __always_inline unsigned long current_top_of_stack(void)
* entry trampoline.
*/
if (IS_ENABLED(CONFIG_USE_X86_SEG_SUPPORT))
- return pcpu_hot.top_of_stack;
+ return const_pcpu_hot.top_of_stack;
return this_cpu_read_stable(pcpu_hot.top_of_stack);
}
--
2.41.0
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] x86/percpu: Return correct variable from current_top_of_stack()
2023-10-24 14:28 [PATCH] x86/percpu: Return correct variable from current_top_of_stack() Uros Bizjak
@ 2023-10-24 15:56 ` Borislav Petkov
2023-10-24 16:05 ` Uros Bizjak
2023-10-24 16:41 ` [tip: x86/percpu] " tip-bot2 for Uros Bizjak
1 sibling, 1 reply; 4+ messages in thread
From: Borislav Petkov @ 2023-10-24 15:56 UTC (permalink / raw)
To: Uros Bizjak
Cc: x86, linux-kernel, Andy Lutomirski, Brian Gerst, Denys Vlasenko,
Ingo Molnar, H . Peter Anvin, Linus Torvalds, Peter Zijlstra,
Thomas Gleixner, Josh Poimboeuf
On Tue, Oct 24, 2023 at 04:28:14PM +0200, Uros Bizjak wrote:
> current_top_of_stack() should return variable from _seg_gs
> qualified named address space when CONFIG_USE_X86_SEG_SUPPORT
> is enbled.
I presume you're sending those two in order to fix stuff like the splat
below which fires in my guest with latest Linus + latest tip/master
lineup.
Because disabling CONFIG_USE_X86_SEG_SUPPORT fixes it.
I'm wondering that close to the merge window whether we should delay
all that new and fancy percpu stuff one more round until it is tested
more widely...
[ 1.623994] kprobes: kprobe jump-optimization is enabled. All kprobes are optimized if possible.
[ 1.627398] HugeTLB: registered 1.00 GiB page size, pre-allocated 0 pages
[ 1.627101] BUG: unable to handle page fault for address: 000000000002f0d8
[ 1.629645] HugeTLB: 16380 KiB vmemmap can be freed for a 1.00 GiB page
[ 1.628158] #PF: supervisor read access in kernel mode
[ 1.628161] #PF: error_code(0x0000) - not-present page
[ 1.628163] PGD 0 P4D 0
[ 1.628167] Oops: 0000 [#1] PREEMPT SMP
[ 1.628171] CPU: 1 PID: 10 Comm: kworker/u32:0 Not tainted 6.6.0-rc7+ #1
[ 1.631566] HugeTLB: registered 2.00 MiB page size, pre-allocated 0 pages
[ 1.629156] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
[ 1.632494] HugeTLB: 28 KiB vmemmap can be freed for a 2.00 MiB page
[ 1.629990] Workqueue: ftrace_check_wq ftrace_check_work_func
[ 1.631041] RIP: 0010:raw_irqentry_exit_cond_resched+0x16/0x50
[ 1.631041] Code: 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 65 f7 05 d4 ff ef 7e ff ff ff 7f 75 21 <48> 8b 05 db ff ef 7e 48 29 e0 48 3d ff 3f 00 00 77 19 65 48 8b 05
[ 1.631041] RSP: 0018:ffffc9000005bab8 EFLAGS: 00010046
[ 1.631041] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000000002f900
[ 1.631041] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc9000005bac8
[ 1.631041] RBP: 0000000000000000 R08: 0000000000000002 R09: 0000000000000001
[ 1.631041] R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
[ 1.631041] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 1.631041] FS: 0000000000000000(0000) GS:ffff88807da40000(0000) knlGS:0000000000000000
[ 1.631041] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1.631041] CR2: 000000000002f0d8 CR3: 0000000002416000 CR4: 00000000003506f0
[ 1.631041] Call Trace:
[ 1.631041] <TASK>
[ 1.631041] ? __die+0x31/0x80
[ 1.631041] ? page_fault_oops+0x160/0x440
[ 1.631041] ? exc_page_fault+0x74/0x150
[ 1.631041] ? asm_exc_page_fault+0x26/0x30
[ 1.631041] ? raw_irqentry_exit_cond_resched+0x16/0x50
[ 1.631041] irqentry_exit+0x21/0x60
[ 1.631041] asm_sysvec_apic_timer_interrupt+0x1a/0x20
[ 1.631041] RIP: 0010:get_symbol_offset+0x26/0x60
[ 1.631041] Code: 90 90 90 90 0f 1f 44 00 00 48 89 f8 48 c1 e8 08 8b 04 85 80 4f 0b 82 48 05 88 af f1 81 81 e7 ff 00 00 00 74 25 31 c9 0f b6 10 <84> d2 79 0e 0f b6 70 01 83 e2 7f c1 e6 07 09 f2 ff c2 ff c2 ff c1
--
Regards/Gruss,
Boris.
https://people.kernel.org/tglx/notes-about-netiquette
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] x86/percpu: Return correct variable from current_top_of_stack()
2023-10-24 15:56 ` Borislav Petkov
@ 2023-10-24 16:05 ` Uros Bizjak
0 siblings, 0 replies; 4+ messages in thread
From: Uros Bizjak @ 2023-10-24 16:05 UTC (permalink / raw)
To: Borislav Petkov
Cc: x86, linux-kernel, Andy Lutomirski, Brian Gerst, Denys Vlasenko,
Ingo Molnar, H . Peter Anvin, Linus Torvalds, Peter Zijlstra,
Thomas Gleixner, Josh Poimboeuf
On Tue, Oct 24, 2023 at 5:56 PM Borislav Petkov <bp@alien8.de> wrote:
>
> On Tue, Oct 24, 2023 at 04:28:14PM +0200, Uros Bizjak wrote:
> > current_top_of_stack() should return variable from _seg_gs
> > qualified named address space when CONFIG_USE_X86_SEG_SUPPORT
> > is enbled.
>
> I presume you're sending those two in order to fix stuff like the splat
> below which fires in my guest with latest Linus + latest tip/master
> lineup.
Yes, the first one is the fix, the second one is only tangentially
related to the fix.
> Because disabling CONFIG_USE_X86_SEG_SUPPORT fixes it.
>
> I'm wondering that close to the merge window whether we should delay
> all that new and fancy percpu stuff one more round until it is tested
> more widely...
The percpu stuff won't be merged for 6.7, it will have to sit out until 6.8.
Thanks,
Uros.
>
> [ 1.623994] kprobes: kprobe jump-optimization is enabled. All kprobes are optimized if possible.
> [ 1.627398] HugeTLB: registered 1.00 GiB page size, pre-allocated 0 pages
> [ 1.627101] BUG: unable to handle page fault for address: 000000000002f0d8
> [ 1.629645] HugeTLB: 16380 KiB vmemmap can be freed for a 1.00 GiB page
> [ 1.628158] #PF: supervisor read access in kernel mode
> [ 1.628161] #PF: error_code(0x0000) - not-present page
> [ 1.628163] PGD 0 P4D 0
> [ 1.628167] Oops: 0000 [#1] PREEMPT SMP
> [ 1.628171] CPU: 1 PID: 10 Comm: kworker/u32:0 Not tainted 6.6.0-rc7+ #1
> [ 1.631566] HugeTLB: registered 2.00 MiB page size, pre-allocated 0 pages
> [ 1.629156] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
> [ 1.632494] HugeTLB: 28 KiB vmemmap can be freed for a 2.00 MiB page
> [ 1.629990] Workqueue: ftrace_check_wq ftrace_check_work_func
> [ 1.631041] RIP: 0010:raw_irqentry_exit_cond_resched+0x16/0x50
> [ 1.631041] Code: 00 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 0f 1f 44 00 00 65 f7 05 d4 ff ef 7e ff ff ff 7f 75 21 <48> 8b 05 db ff ef 7e 48 29 e0 48 3d ff 3f 00 00 77 19 65 48 8b 05
> [ 1.631041] RSP: 0018:ffffc9000005bab8 EFLAGS: 00010046
> [ 1.631041] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000000002f900
> [ 1.631041] RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffc9000005bac8
> [ 1.631041] RBP: 0000000000000000 R08: 0000000000000002 R09: 0000000000000001
> [ 1.631041] R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000
> [ 1.631041] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
> [ 1.631041] FS: 0000000000000000(0000) GS:ffff88807da40000(0000) knlGS:0000000000000000
> [ 1.631041] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 1.631041] CR2: 000000000002f0d8 CR3: 0000000002416000 CR4: 00000000003506f0
> [ 1.631041] Call Trace:
> [ 1.631041] <TASK>
> [ 1.631041] ? __die+0x31/0x80
> [ 1.631041] ? page_fault_oops+0x160/0x440
> [ 1.631041] ? exc_page_fault+0x74/0x150
> [ 1.631041] ? asm_exc_page_fault+0x26/0x30
> [ 1.631041] ? raw_irqentry_exit_cond_resched+0x16/0x50
> [ 1.631041] irqentry_exit+0x21/0x60
> [ 1.631041] asm_sysvec_apic_timer_interrupt+0x1a/0x20
> [ 1.631041] RIP: 0010:get_symbol_offset+0x26/0x60
> [ 1.631041] Code: 90 90 90 90 0f 1f 44 00 00 48 89 f8 48 c1 e8 08 8b 04 85 80 4f 0b 82 48 05 88 af f1 81 81 e7 ff 00 00 00 74 25 31 c9 0f b6 10 <84> d2 79 0e 0f b6 70 01 83 e2 7f c1 e6 07 09 f2 ff c2 ff c2 ff c1
>
> --
> Regards/Gruss,
> Boris.
>
> https://people.kernel.org/tglx/notes-about-netiquette
^ permalink raw reply [flat|nested] 4+ messages in thread
* [tip: x86/percpu] x86/percpu: Return correct variable from current_top_of_stack()
2023-10-24 14:28 [PATCH] x86/percpu: Return correct variable from current_top_of_stack() Uros Bizjak
2023-10-24 15:56 ` Borislav Petkov
@ 2023-10-24 16:41 ` tip-bot2 for Uros Bizjak
1 sibling, 0 replies; 4+ messages in thread
From: tip-bot2 for Uros Bizjak @ 2023-10-24 16:41 UTC (permalink / raw)
To: linux-tip-commits
Cc: Uros Bizjak, Ingo Molnar, Andy Lutomirski, Brian Gerst,
Denys Vlasenko, H. Peter Anvin, Linus Torvalds, Josh Poimboeuf,
Sean Christopherson, x86, linux-kernel
The following commit has been merged into the x86/percpu branch of tip:
Commit-ID: 0548eb067ed664b93043e033295ca71e3e706245
Gitweb: https://git.kernel.org/tip/0548eb067ed664b93043e033295ca71e3e706245
Author: Uros Bizjak <ubizjak@gmail.com>
AuthorDate: Tue, 24 Oct 2023 16:28:14 +02:00
Committer: Ingo Molnar <mingo@kernel.org>
CommitterDate: Tue, 24 Oct 2023 18:37:20 +02:00
x86/percpu: Return correct variable from current_top_of_stack()
current_top_of_stack() should return variable from _seg_gs
qualified named address space when CONFIG_USE_X86_SEG_SUPPORT=y
is enbled.
Fixes: ed2f752e0e0a ("x86/percpu: Introduce const-qualified const_pcpu_hot to micro-optimize code generation")
Signed-off-by: Uros Bizjak <ubizjak@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Link: https://lore.kernel.org/r/20231024142830.3226-1-ubizjak@gmail.com
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>
---
arch/x86/include/asm/processor.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index b47a997..f20e876 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -519,7 +519,7 @@ static __always_inline unsigned long current_top_of_stack(void)
* entry trampoline.
*/
if (IS_ENABLED(CONFIG_USE_X86_SEG_SUPPORT))
- return pcpu_hot.top_of_stack;
+ return const_pcpu_hot.top_of_stack;
return this_cpu_read_stable(pcpu_hot.top_of_stack);
}
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2023-10-24 16:41 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2023-10-24 14:28 [PATCH] x86/percpu: Return correct variable from current_top_of_stack() Uros Bizjak
2023-10-24 15:56 ` Borislav Petkov
2023-10-24 16:05 ` Uros Bizjak
2023-10-24 16:41 ` [tip: x86/percpu] " tip-bot2 for Uros Bizjak
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