CVE-2024-57946 Information

Description

In the Linux kernel the following vulnerability has been resolved:

virtio-blk: don’t keep queue frozen during system suspend

Commit 4ce6e2db00de (irtio-blk: Ensure no requests in virtqueues before deleting vqs.) replaces queue quiesce with queue freeze in virtio-blk’s PM callbacks. And the motivation is to drain inflight IOs before suspending.

block layer’s queue freeze looks very handy but it is also easy to cause deadlock such as any attempt to call into bio_queue_enter() may run into deadlock if the queue is frozen in current context. There are all kinds of ->suspend() called in suspend context so keeping queue frozen in the whole suspend context isn’t one good idea. And Marek reported lockdep warning[1] caused by virtio-blk’s freeze queue in virtblk_freeze().

[1] https://lore.kernel.org/linux-block/ca16370e-d646-4eee-b9cc-87277c89c43c@samsung.com/

Given the motivation is to drain in-flight IOs it can be done by calling freeze & unfreeze meantime restore to previous behavior by keeping queue quiesced during suspend.

Reference

https://git.kernel.org/stable/c/12c0ddd6c551c1e438b087f874b4f1223a75f7ea https://git.kernel.org/stable/c/6dea8e3de59928974bf157dd0499d3958d744ae4 https://git.kernel.org/stable/c/7678abee0867e6b7fb89aa40f6e9f575f755fb37 https://git.kernel.org/stable/c/92d5139b91147ab372a17daf5dc27a5b9278e516 https://git.kernel.org/stable/c/9ca428c6397abaa8c38f5c69133a2299e1efbbf2 https://git.kernel.org/stable/c/9e323f856cf4963120e0e3892a84ef8bd764a0e4 https://git.kernel.org/stable/c/d738f3215bb4f88911ff4579780a44960c8e0ca5