? hrtimer_interrupt ? watchdog_timer_fn ?
__sysvec_apic_timer_interrupt ? __pfx_watchdog_timer_fn ?
sysvec_apic_timer_interrupt ? __hrtimer_run_queues ?
hrtimer_interrupt ? asm_sysvec_apic_timer_interrupt ?
_raw_spin_unlock_irqrestore ? __sysvec_apic_timer_interrupt ?
sysvec_apic_timer_interrupt accept_memory try_to_accept_memory
do_huge_pmd_anonymous_page get_page_from_freelist __handle_mm_fault
__alloc_pages __folio_alloc ? __tdx_hypercall handle_mm_fault
vma_alloc_folio do_user_addr_fault do_huge_pmd_anonymous_page
exc_page_fault ? __do_huge_pmd_anonymous_page asm_exc_page_fault
__handle_mm_fault When the local irq is enabled at the end of
accept_memory(), the softlockup detects that the watchdog on single
CPU has not been fed for a while. That is to say, even other CPUs will
not be blocked by spinlock, the current CPU might be stunk with local
irq disabled for a while, which hurts not only nmi watchdog but also
softlockup. Chao Gao pointed out that the memory accept could be time
costly and there was similar report before. Thus to avoid any
softlocup detection during this stage, give the softlockup a flag to
skip the timeout check at the end of accept_memory(), by invoking
touch_softlockup_watchdog().
">
,?,hrtimer_interrupt,?,watchdog_timer_fn,?
__sysvec_apic_timer_interrupt,?,__pfx_watchdog_timer_fn,?
sysvec_apic_timer_interrupt,,?,__hrtimer_run_queues,,?
hrtimer_interrupt,?,asm_sysvec_apic_timer_interrupt,?
_raw_spin_unlock_irqrestore,?,__sysvec_apic_timer_interrupt,?
sysvec_apic_timer_interrupt,accept_memory,try_to_accept_memory
do_huge_pmd_anonymous_page,get_page_from_freelist,__handle_mm_fault
__alloc_pages,__folio_alloc,?,__tdx_hypercall,handle_mm_fault
vma_alloc_folio,do_user_addr_fault,do_huge_pmd_anonymous_page
exc_page_fault,?,__do_huge_pmd_anonymous_page,asm_exc_page_fault
__handle_mm_fault,When,the,local,irq,is,enabled,at,the,end,of
accept_memory(),,the,softlockup,detects,that,the,watchdog,on,single
CPU,has,not,been,fed,for,a,while.,That,is,to,say,,even,other,CPUs,will
not,be,blocked,by,spinlock,,the,current,CPU,might,be,stunk,with,local
irq,disabled,for,a,while,,which,hurts,not,only,nmi,watchdog,but,also
softlockup.,Chao,Gao,pointed,out,that,the,memory,accept,could,be,time
costly,and,there,was,similar,report,before.,Thus,to,avoid,any
softlocup,detection,during,this,stage,,give,the,softlockup,a,flag,to
skip,the,timeout,check,at,the,end,of,accept_memory(),,by,invoking
touch_softlockup_watchdog().
">
SecuritySpace - CVE-2024-36936
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CVE ID: | CVE-2024-36936 |
Description: | In the Linux kernel, the following vulnerability has been resolved:
efi/unaccepted: touch soft lockup during memory accept Commit
50e782a86c98 ("efi/unaccepted: Fix soft lockups caused by parallel
memory acceptance") has released the spinlock so other CPUs can do
memory acceptance in parallel and not triggers softlockup on other
CPUs. However the softlock up was intermittent shown up if the memory
of the TD guest is large, and the timeout of softlockup is set to 1
second: RIP: 0010:_raw_spin_unlock_irqrestore Call Trace: ?
__hrtimer_run_queues ? hrtimer_interrupt ? watchdog_timer_fn ?
__sysvec_apic_timer_interrupt ? __pfx_watchdog_timer_fn ?
sysvec_apic_timer_interrupt ? __hrtimer_run_queues ?
hrtimer_interrupt ? asm_sysvec_apic_timer_interrupt ?
_raw_spin_unlock_irqrestore ? __sysvec_apic_timer_interrupt ?
sysvec_apic_timer_interrupt accept_memory try_to_accept_memory
do_huge_pmd_anonymous_page get_page_from_freelist __handle_mm_fault
__alloc_pages __folio_alloc ? __tdx_hypercall handle_mm_fault
vma_alloc_folio do_user_addr_fault do_huge_pmd_anonymous_page
exc_page_fault ? __do_huge_pmd_anonymous_page asm_exc_page_fault
__handle_mm_fault When the local irq is enabled at the end of
accept_memory(), the softlockup detects that the watchdog on single
CPU has not been fed for a while. That is to say, even other CPUs will
not be blocked by spinlock, the current CPU might be stunk with local
irq disabled for a while, which hurts not only nmi watchdog but also
softlockup. Chao Gao pointed out that the memory accept could be time
costly and there was similar report before. Thus to avoid any
softlocup detection during this stage, give the softlockup a flag to
skip the timeout check at the end of accept_memory(), by invoking
touch_softlockup_watchdog().
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Test IDs: |
None available |
Cross References: |
Common Vulnerability Exposure (CVE) ID: CVE-2024-36936
https://git.kernel.org/stable/c/1c5a1627f48105cbab81d25ec2f72232bfaa8185
https://git.kernel.org/stable/c/1c5a1627f48105cbab81d25ec2f72232bfaa8185
https://git.kernel.org/stable/c/781e34b736014188ba9e46a71535237313dcda81
https://git.kernel.org/stable/c/781e34b736014188ba9e46a71535237313dcda81
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