CVE-2024-39476

Summary

In the Linux kernel, the following vulnerability has been resolved:

md/raid5: fix deadlock that raid5d() wait for itself to clear MD_SB_CHANGE_PENDING

Xiao reported that lvm2 test lvconvert-raid-takeover.sh can hang with small possibility, the root cause is exactly the same as commit bed9e27baf52 ("Revert "md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d"")

However, Dan reported another hang after that, and junxiao investigated the problem and found out that this is caused by plugged bio can't issue from raid5d().

Current implementation in raid5d() has a weird dependence:

  1. md_check_recovery() from raid5d() must hold 'reconfig_mutex' to clear MD_SB_CHANGE_PENDING;
  2. raid5d() handles IO in a deadloop, until all IO are issued;
  3. IO from raid5d() must wait for MD_SB_CHANGE_PENDING to be cleared;

This behaviour is introduce before v2.6, and for consequence, if other context hold 'reconfig_mutex', and md_check_recovery() can't update super_block, then raid5d() will waste one cpu 100% by the deadloop, until 'reconfig_mutex' is released.

Refer to the implementation from raid1 and raid10, fix this problem by skipping issue IO if MD_SB_CHANGE_PENDING is still set after md_check_recovery(), daemon thread will be woken up when 'reconfig_mutex' is released. Meanwhile, the hang problem will be fixed as well.

Affected Software

VendorProductVersion RangeStatus
LinuxLinuxf3d55bd5b7b928ad82f8075d89c908702f3593ab < b32aa95843cac6b12c2c014d40fca18aef24a347affected
LinuxLinux1c00bb624cd084e2006520ad0edacaff0fb941c4 < 634ba3c97ec413cb10681c7b196db43ee461ecf4affected
LinuxLinux782b3e71c957991ac8ae53318bc369049d49bb53 < aa64464c8f4d2ab92f6d0b959a1e0767b829d787affected
LinuxLinux9e86dffd0b02594d2e7c60c6db9e889c0395414b < 098d54934814dd876963abfe751c3b1cf7fbe56aaffected
LinuxLinux5e2cf333b7bd5d3e62595a44d598a254c697cd74 < 3f8d5e802d4cedd445f9a89be8c3fd2d0e99024baffected
LinuxLinux5e2cf333b7bd5d3e62595a44d598a254c697cd74 < cd2538e5af495b3c747e503db346470fc1ffc447affected
LinuxLinux5e2cf333b7bd5d3e62595a44d598a254c697cd74 < e332a12f65d8fed8cf63bedb4e9317bb872b9ac7affected
LinuxLinux5e2cf333b7bd5d3e62595a44d598a254c697cd74 < 151f66bb618d1fd0eeb84acb61b4a9fa5d8bb0faaffected
LinuxLinux7d808fe6af8409cf9f46ed2b10840e5788985e9baffected
LinuxLinux2cab058f2b147e0b7c01546ba00445e5701861f5affected
LinuxLinux91962e40ec3d26e291db230cd45b302da2aff200affected
LinuxLinux4.19.262 < 4.19.316affected
LinuxLinux5.4.220 < 5.4.278affected
LinuxLinux5.10.150 < 5.10.219affected
LinuxLinux5.15.75 < 5.15.161affected
LinuxLinux4.14.296 < 4.15affected
LinuxLinux5.19.17 < 5.20affected
LinuxLinux6.0.3 < 6.1affected
LinuxLinux6.1affected
LinuxLinux0 < 6.1unaffected
LinuxLinux4.19.316 <= 4.19.*unaffected
LinuxLinux5.4.278 <= 5.4.*unaffected
LinuxLinux5.10.219 <= 5.10.*unaffected
LinuxLinux5.15.161 <= 5.15.*unaffected
LinuxLinux6.1.94 <= 6.1.*unaffected
LinuxLinux6.6.34 <= 6.6.*unaffected
LinuxLinux6.9.5 <= 6.9.*unaffected
LinuxLinux6.10 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

CVE Program Container

Additional References

References