CVE-2025-22053: net: ibmveth: make veth_pool_store stop hanging
In the Linux kernel, the following vulnerability has been resolved:
net: ibmveth: make vethpoolstore stop hanging
v2: - Created a single error handling unlock and exit in vethpoolstore - Greatly expanded commit message with previous explanatory-only text
Summary: Use rtnlmutex to synchronize vethpoolstore with itself, ibmvethclose and ibmvethopen, preventing multiple calls in a row to napidisable.
Background: Two (or more) threads could call vethpoolstore through writing to /sys/devices/vio/30000002/pool/. You can do this easily with a little shell script. This causes a hang.
I configured LOCKDEP, compiled ibmveth.c with DEBUG, and built a new kernel. I ran this test again and saw:
Setting pool0/active to 0 Setting pool1/active to 1 [ 73.911067][ T4365] ibmveth 30000002 eth0: close starting Setting pool1/active to 1 Setting pool1/active to 0 [ 73.911367][ T4366] ibmveth 30000002 eth0: close starting [ 73.916056][ T4365] ibmveth 30000002 eth0: close complete [ 73.916064][ T4365] ibmveth 30000002 eth0: open starting [ 110.808564][ T712] systemd-journald[712]: Sent WATCHDOG=1 notification. [ 230.808495][ T712] systemd-journald[712]: Sent WATCHDOG=1 notification. [ 243.683786][ T123] INFO: task stress.sh:4365 blocked for more than 122 seconds. [ 243.683827][ T123] Not tainted 6.14.0-01103-g2df0c02dab82-dirty #8 [ 243.683833][ T123] "echo 0 > /proc/sys/kernel/hungtasktimeoutsecs" disables this message. [ 243.683838][ T123] task:stress.sh state:D stack:28096 pid:4365 tgid:4365 ppid:4364 taskflags:0x400040 flags:0x00042000 [ 243.683852][ T123] Call Trace: [ 243.683857][ T123] [c00000000c38f690] [0000000000000001] 0x1 (unreliable) [ 243.683868][ T123] [c00000000c38f840] [c00000000001f908] switchto+0x318/0x4e0 [ 243.683878][ T123] [c00000000c38f8a0] [c000000001549a70] schedule+0x500/0x12a0 [ 243.683888][ T123] [c00000000c38f9a0] [c00000000154a878] schedule+0x68/0x210 [ 243.683896][ T123] [c00000000c38f9d0] [c00000000154ac80] schedulepreemptdisabled+0x30/0x50 [ 243.683904][ T123] [c00000000c38fa00] [c00000000154dbb0] mutexlock+0x730/0x10f0 [ 243.683913][ T123] [c00000000c38fb10] [c000000001154d40] napienable+0x30/0x60 [ 243.683921][ T123] [c00000000c38fb40] [c000000000f4ae94] ibmvethopen+0x68/0x5dc [ 243.683928][ T123] [c00000000c38fbe0] [c000000000f4aa20] vethpoolstore+0x220/0x270 [ 243.683936][ T123] [c00000000c38fc70] [c000000000826278] sysfskfwrite+0x68/0xb0 [ 243.683944][ T123] [c00000000c38fcb0] [c0000000008240b8] kernfsfopwriteiter+0x198/0x2d0 [ 243.683951][ T123] [c00000000c38fd00] [c00000000071b9ac] vfswrite+0x34c/0x650 [ 243.683958][ T123] [c00000000c38fdc0] [c00000000071bea8] ksyswrite+0x88/0x150 [ 243.683966][ T123] [c00000000c38fe10] [c0000000000317f4] systemcallexception+0x124/0x340 [ 243.683973][ T123] [c00000000c38fe50] [c00000000000d05c] systemcallvectoredcommon+0x15c/0x2ec ... [ 243.684087][ T123] Showing all locks held in the system: [ 243.684095][ T123] 1 lock held by khungtaskd/123: [ 243.684099][ T123] #0: c00000000278e370 (rcureadlock){....}-{1:2}, at: debugshowalllocks+0x50/0x248 [ 243.684114][ T123] 4 locks held by stress.sh/4365: [ 243.684119][ T123] #0: c00000003a4cd3f8 (sbwriters#3){.+.+}-{0:0}, at: ksyswrite+0x88/0x150 [ 243.684132][ T123] #1: c000000041aea888 (&of->mutex#2){+.+.}-{3:3}, at: kernfsfopwriteiter+0x154/0x2d0 [ 243.684143][ T123] #2: c0000000366fb9a8 (kn->active#64){.+.+}-{0:0}, at: kernfsfopwriteiter+0x160/0x2d0 [ 243.684155][ T123] #3: c000000035ff4cb8 (&dev->lock){+.+.}-{3:3}, at: napienable+0x30/0x60 [ 243.684166][ T123] 5 locks held by stress.sh/4366: [ 243.684170][ T123] #0: c00000003a4cd3f8 (sbwriters#3){.+.+}-{0:0}, at: ksyswrite+0x88/0x150 [ 243. ---truncated---