Affected: Linux

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

media: vsp1: Replace vb2_is_streaming() with vb2_start_streaming_called()

The vsp1 driver uses the vb2_is_streaming() function in its .buf_queue() handler to check if the .start_streaming() operation has been called, and decide whether to just add the buffer to an internal queue, or also trigger a hardware run. vb2_is_streaming() relies on the vb2_queue structure's streaming field, which used to be set only after calling the .start_streaming() operation.

Commit a10b21532574 ("media: vb2: add (un)prepare_streaming queue ops") changed this, setting the .streaming field in vb2_core_streamon() before enqueuing buffers to the driver and calling .start_streaming(). This broke the vsp1 driver which now believes that .start_streaming() has been called when it hasn't, leading to a crash:

[ 881.058705] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000020 [ 881.067495] Mem abort info: [ 881.070290] ESR = 0x0000000096000006 [ 881.074042] EC = 0x25: DABT (current EL), IL = 32 bits [ 881.079358] SET = 0, FnV = 0 [ 881.082414] EA = 0, S1PTW = 0 [ 881.085558] FSC = 0x06: level 2 translation fault [ 881.090439] Data abort info: [ 881.093320] ISV = 0, ISS = 0x00000006 [ 881.097157] CM = 0, WnR = 0 [ 881.100126] user pgtable: 4k pages, 48-bit VAs, pgdp=000000004fa51000 [ 881.106573] [0000000000000020] pgd=080000004f36e003, p4d=080000004f36e003, pud=080000004f7ec003,…