CVE-2024-53184

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

um: ubd: Do not use drvdata in release

The drvdata is not available in release. Let's just use container_of() to get the ubd instance. Otherwise, removing a ubd device will result in a crash:

RIP: 0033:blkmqfreetagset+0x1f/0xba RSP: 00000000e2083bf0 EFLAGS: 00010246 RAX: 000000006021463a RBX: 0000000000000348 RCX: 0000000062604d00 RDX: 0000000004208060 RSI: 00000000605241a0 RDI: 0000000000000348 RBP: 00000000e2083c10 R08: 0000000062414010 R09: 00000000601603f7 R10: 000000000000133a R11: 000000006038c4bd R12: 0000000000000000 R13: 0000000060213a5c R14: 0000000062405d20 R15: 00000000604f7aa0 Kernel panic - not syncing: Segfault with no mm CPU: 0 PID: 17 Comm: kworker/0:1 Not tainted 6.8.0-rc3-00107-gba3f67c11638 #1 Workqueue: events mcworkproc Stack: 00000000 604f7ef0 62c5d000 62405d20 e2083c30 6002c776 6002c755 600e47ff e2083c60 6025ffe3 04208060 603d36e0 Call Trace: [<6002c776>] ubddevicerelease+0x21/0x55 [<6002c755>] ? ubddevicerelease+0x0/0x55 [<600e47ff>] ? kfree+0x0/0x100 [<6025ffe3>] devicerelease+0x70/0xba [<60381d6a>] kobjectput+0xb5/0xe2 [<6026027b>] putdevice+0x19/0x1c [<6026a036>] platformdeviceput+0x26/0x29 [<6026ac5a>] platformdeviceunregister+0x2c/0x2e [<6002c52e>] ubdremove+0xb8/0xd6 [<6002bb74>] ? mconsolereply+0x0/0x50 [<6002b926>] mconsoleremove+0x160/0x1cc [<6002bbbc>] ? mconsolereply+0x48/0x50 [<6003379c>] ? umsetsignals+0x3b/0x43 [<60061c55>] ? updateminvruntime+0x14/0x70 [<6006251f>] ? dequeuetaskfair+0x164/0x235 [<600620aa>] ? updatecfs_group+0x0/0x40 [<603a0e77>] ? _schedule+0x0/0x3ed [<60033761>] ? umsetsignals+0x0/0x43 [<6002af6a>] mcworkproc+0x77/0x91 [<600520b4>] processscheduledworks+0x1af/0x2c3 [<6004ede3>] ? assignwork+0x0/0x58 [<600527a1>] workerthread+0x2f7/0x37a [<6004ee3b>] ? setpfworker+0x0/0x64 [<6005765d>] ? archlocalirqsave+0x0/0x2d [<60058e07>] ? kthreadexit+0x0/0x3a [<600524aa>] ? workerthread+0x0/0x37a [<60058f9f>] kthread+0x130/0x135 [<6002068e>] newthreadhandler+0x85/0xb6