vm_page: Clear VM_ALLOC_NOCREAT in vm_page_grab_pflags()
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Authored by markj on Fri, Aug 1, 11:38 PM.

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alc
dougm
kib

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rG9a1b3303352b: vm_page: Clear VM_ALLOC_NOCREAT in vm_page_grab_pflags()

Summary

Otherwise vm_page_grab_zero_partial() and vm_page_grab_pages() can pass
it to vm_page_alloc_*(), which results in an assertion failure since
that flag is meaningless when allocating a page:

panic: invalid request 0x8400
cpuid = 0
time = 1754074745
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x49/frame 0xfffffe00542859c0
vpanic() at vpanic+0x1ea/frame 0xfffffe0054285b00
panic() at panic+0x43/frame 0xfffffe0054285b60
vm_page_alloc_domain_iter() at vm_page_alloc_domain_iter+0x720/frame 0xfffffe0054285be0
vm_page_grab_zero_partial() at vm_page_grab_zero_partial+0x1d4/frame 0xfffffe0054285c90
shm_fspacectl() at shm_fspacectl+0x1cd/frame 0xfffffe0054285d30
kern_fspacectl() at kern_fspacectl+0x49f/frame 0xfffffe0054285db0
sys_fspacectl() at sys_fspacectl+0x5b/frame 0xfffffe0054285e00
amd64_syscall() at amd64_syscall+0x29c/frame 0xfffffe0054285f30
fast_syscall_common() at fast_syscall_common+0xf8/frame 0xfffffe0054285f30

Reported by: syzkaller

Diff Detail

Repository

rG FreeBSD src repository

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Lint Not Applicable

Unit

Tests Not Applicable

Event Timeline

markj created this revision.Fri, Aug 1, 11:38 PM

Herald added a subscriber: imp. · View Herald TranscriptFri, Aug 1, 11:38 PM

markj requested review of this revision.Fri, Aug 1, 11:38 PM

Harbormaster completed remote builds in B65911: Diff 159614.Fri, Aug 1, 11:38 PM

May be its time to switch from &~() to &, i.e. allow explicitly listed flags.

This revision is now accepted and ready to land.Sat, Aug 2, 1:07 AM

alc accepted this revision.Sat, Aug 2, 2:48 AM

In D51692#1180692, @kib wrote:

May be its time to switch from &~() to &, i.e. allow explicitly listed flags.

Most of the VM_ALLOC_* flags should be passed through, so the length of the list wouldn't change much. I also like that we explicitly clear the NOWAIT, WAITOK, WAITFAIL flags here.

Closed by commit rG9a1b3303352b: vm_page: Clear VM_ALLOC_NOCREAT in vm_page_grab_pflags() (authored by markj). · Explain WhyMon, Aug 4, 2:28 PM

This revision was automatically updated to reflect the committed changes.

markj added a commit: rG9a1b3303352b: vm_page: Clear VM_ALLOC_NOCREAT in vm_page_grab_pflags().