In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
fs\/dax: check zero or empty entry before converting xarray entry<\/p>\n
Calling dax_to_folio() with empty entry causes kernel panic below when
\nbooting a VM with DAX enabled storage.<\/p>\n
This patch checks empty entry before calling dax_to_folio() on
\ndax_associate_entry(), dax_disassociate_entry(), and dax_busy_page().<\/p>\n
Commit 98c183a4fccf (“fs\/dax: don’t disassociate zero page entries”) added
\nguards in the associate and disassociate paths, but the guards still come
\nafter dax_to_folio(), and dax_busy_page() still has the same problem.<\/p>\n
[ 0.737679] EXT4-fs (pmem0p1): mounted filesystem 79676804-7c8b-491a-b2a6-9bae3c72af70 ro with ordered data mode. Quota mode: disabled.
\n[ 0.737891] VFS: Mounted root (ext4 filesystem) readonly on device 259:1.
\n[ 0.739119] devtmpfs: mounted
\n[ 0.739476] Freeing unused kernel memory: 1920K
\n[ 0.740156] Run \/sbin\/init as init process
\n[ 0.740229] with arguments:
\n[ 0.740286] \/sbin\/init
\n[ 0.740321] with environment:
\n[ 0.740369] HOME=\/
\n[ 0.740400] TERM=linux
\n[ 0.743162] Unable to handle kernel paging request at virtual address fffffdffbf000008
\n[ 0.743285] Mem abort info:
\n[ 0.743316] ESR = 0x0000000096000006
\n[ 0.743371] EC = 0x25: DABT (current EL), IL = 32 bits
\n[ 0.743444] SET = 0, FnV = 0
\n[ 0.743489] EA = 0, S1PTW = 0
\n[ 0.743545] FSC = 0x06: level 2 translation fault
\n[ 0.743610] Data abort info:
\n[ 0.743656] ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000
\n[ 0.743720] CM = 0, WnR = 0, TnD = 0, TagAccess = 0
\n[ 0.743785] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
\n[ 0.743848] swapper pgtable: 4k pages, 48-bit VAs, pgdp=00000000b9d17000
\n[ 0.743931] [fffffdffbf000008] pgd=10000000bfa3d403, p4d=10000000bfa3d403, pud=1000000040bfe403, pmd=0000000000000000
\n[ 0.744070] Internal error: Oops: 0000000096000006 [#1] SMP
\n[ 0.748888] CPU: 0 UID: 0 PID: 1 Comm: init Not tainted 6.18.4 #1 NONE
\n[ 0.749421] pstate: 004000c5 (nzcv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=–)
\n[ 0.749969] pc : dax_disassociate_entry.constprop.0+0x20\/0x50
\n[ 0.750444] lr : dax_insert_entry+0xcc\/0x408
\n[ 0.750802] sp : ffff80008000b9e0
\n[ 0.751083] x29: ffff80008000b9e0 x28: 0000000000000000 x27: 0000000000000000
\n[ 0.751682] x26: 0000000001963d01 x25: ffff0000004f7d90 x24: 0000000000000000
\n[ 0.752264] x23: 0000000000000000 x22: ffff80008000bcc8 x21: 0000000000000011
\n[ 0.752836] x20: ffff80008000ba90 x19: 0000000001963d01 x18: 0000000000000000
\n[ 0.753407] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
\n[ 0.753970] x14: ffffbf3154b9ae70 x13: 0000000000000000 x12: ffffbf3154b9ae70
\n[ 0.754548] x11: ffffffffffffffff x10: 0000000000000000 x9 : 0000000000000000
\n[ 0.755122] x8 : 000000000000000d x7 : 000000000000001f x6 : 0000000000000000
\n[ 0.755707] x5 : 0000000000000000 x4 : 0000000000000000 x3 : fffffdffc0000000
\n[ 0.756287] x2 : 0000000000000008 x1 : 0000000040000000 x0 : fffffdffbf000000
\n[ 0.756871] Call trace:
\n[ 0.757107] dax_disassociate_entry.constprop.0+0x20\/0x50 (P)
\n[ 0.757592] dax_iomap_pte_fault+0x4fc\/0x808
\n[ 0.757951] dax_iomap_fault+0x28\/0x30
\n[ 0.758258] ext4_dax_huge_fault+0x80\/0x2dc
\n[ 0.758594] ext4_dax_fault+0x10\/0x3c
\n[ 0.758892] __do_fault+0x38\/0x12c
\n[ 0.759175] __handle_mm_fault+0x530\/0xcf0
\n[ 0.759518] handle_mm_fault+0xe4\/0x230
\n[ 0.759833] do_page_fault+0x17c\/0x4dc
\n[ 0.760144] do_translation_fault+0x30\/0x38
\n[ 0.760483] do_mem_abort+0x40\/0x8c
\n[ 0.760771] el0_ia+0x4c\/0x170
\n[ 0.761032] el0t_64_sync_handler+0xd8\/0xdc
\n[ 0.761371] el0t_64_sync+0x168\/0x16c
\n[ 0.761677] Code: f9453021 f2dfbfe3 cb813080 8b001860 (f9400401)
\n[ 0.762168] —[ end trace 0000000000000000 ]—
\n[ 0.762550] note: init[1] exited with irqs disabled
\n[ 0.762631] Kernel panic – not syncing: Attempted to kill init! exitcode=0x0000000b<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
fs\/dax: check zero or empty entry before converting xarray entry<\/p>\n
Calling dax_to_folio() with empty entry causes kernel panic below<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-33328","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/33328","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=33328"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=33328"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=33328"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}