CVE-2025-21688 Information

Feb 11, 2025 cve

Description

In the Linux kernel the following vulnerability has been resolved:

drm/v3d: Assign job pointer to NULL before signaling the fence

In commit e4b5ccd392b9 (\drm/v3d: Ensure job pointer is set to NULL after job completion) we introduced a change to assign the job pointer to NULL after completing a job indicating job completion.

However this approach created a race condition between the DRM scheduler workqueue and the IRQ execution thread. As soon as the fence is signaled in the IRQ execution thread a new job starts to be executed. This results in a race condition where the IRQ execution thread sets the job pointer to NULL simultaneously as the run_job() function assigns a new job to the pointer.

This race condition can lead to a NULL pointer dereference if the IRQ execution thread sets the job pointer to NULL after run_job() assigns it to the new job. When the new job completes and the GPU emits an interrupt v3d_irq() is triggered potentially causing a crash.

[ 466.310099] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000c0 [ 466.318928] Mem abort info: [ 466.321723] ESR = 0x0000000096000005 [ 466.325479] EC = 0x25: DABT (current EL) IL = 32 bits [ 466.330807] SET = 0 FnV = 0 [ 466.333864] EA = 0 S1PTW = 0 [ 466.337010] FSC = 0x05: level 1 translation fault [ 466.341900] Data abort info: [ 466.344783] ISV = 0 ISS = 0x00000005 ISS2 = 0x00000000 [ 466.350285] CM = 0 WnR = 0 TnD = 0 TagAccess = 0 [ 466.355350] GCS = 0 Overlay = 0 DirtyBit = 0 Xs = 0 [ 466.360677] user pgtable: 4k pages 39-bit VAs pgdp=0000000089772000 [ 466.367140] [00000000000000c0] pgd=0000000000000000 p4d=0000000000000000 pud=0000000000000000 [ 466.375875] Internal error: Oops: 0000000096000005 [1] PREEMPT SMP [ 466.382163] Modules linked in: rfcomm snd_seq_dummy snd_hrtimer snd_seq snd_seq_device algif_hash algif_skcipher af_alg bnep binfmt_misc vc4 snd_soc_hdmi_codec drm_display_helper cec brcmfmac_wcc spidev rpivid_hevc(C) drm_client_lib brcmfmac hci_uart drm_dma_helper pisp_be btbcm brcmutil snd_soc_core aes_ce_blk v4l2_mem2mem bluetooth aes_ce_cipher snd_compress videobuf2_dma_contig ghash_ce cfg80211 gf128mul snd_pcm_dmaengine videobuf2_memops ecdh_generic sha2_ce ecc videobuf2_v4l2 snd_pcm v3d sha256_arm64 rfkill videodev snd_timer sha1_ce libaes gpu_sched snd videobuf2_common sha1_generic drm_shmem_helper mc rp1_pio drm_kms_helper raspberrypi_hwmon spi_bcm2835 gpio_keys i2c_brcmstb rp1 raspberrypi_gpiomem rp1_mailbox rp1_adc nvmem_rmem uio_pdrv_genirq uio i2c_dev drm ledtrig_pattern drm_panel_orientation_quirks backlight fuse dm_mod ip_tables x_tables ipv6 [ 466.458429] CPU: 0 UID: 1000 PID: 2008 Comm: chromium Tainted: G C 6.13.0-v8+ 18 [ 466.467336] Tainted: [C]=CRAP [ 466.470306] Hardware name: Raspberry Pi 5 Model B Rev 1.0 (DT) [ 466.476157] pstate: 404000c9 (nZcv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=–) [ 466.483143] pc : v3d_irq+0x118/0x2e0 [v3d] [ 466.487258] lr : __handle_irq_event_percpu+0x60/0x228 [ 466.492327] sp : ffffffc080003ea0 [ 466.495646] x29: ffffffc080003ea0 x28: ffffff80c0c94200 x27: 0000000000000000 [ 466.502807] x26: ffffffd08dd81d7b x25: ffffff80c0c94200 x24: ffffff8003bdc200 [ 466.509969] x23: 0000000000000001 x22: 00000000000000a7 x21: 0000000000000000 [ 466.517130] x20: ffffff8041bb0000 x19: 0000000000000001 x18: 0000000000000000 [ 466.524291] x17: ffffffafadfb0000 x16: ffffffc080000000 x15: 0000000000000000 [ 466.531452] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000 [ 466.538613] x11: 0000000000000000 x10: 0000000000000000 x9 : ffffffd08c527eb0 [ 466.545777] x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000 [ 466.552941] x5 : ffffffd08c4100d0 x4 : ffffffafadfb0000 x3 : ffffffc080003f70 [ 466.560102] x2 : ffffffc0829e8058 x1 : 0000000000000001 x0 : 0000000000000000 [ 466.567263] Call trace: [ 466.569711] v3d_irq+0x118/0x2e0 [v3d] (P) [ 466.

truncated—

Reference

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