linux_dsm_epyc7002/include
KaiChieh Chuang bbfaa7d36c
ASoC: dpcm: prevent snd_soc_dpcm use after free
The dpcm get from fe_clients/be_clients
may be free before use

Add a spin lock at snd_soc_card level,
to protect the dpcm instance.
The lock may be used in atomic context, so use spin lock.

possible race condition between
void dpcm_be_disconnect(
	...
	list_del(&dpcm->list_be);
	list_del(&dpcm->list_fe);
	kfree(dpcm);
	...

and
	for_each_dpcm_fe()
	for_each_dpcm_be*()

race condition example
Thread 1:
    snd_soc_dapm_mixer_update_power()
        -> soc_dpcm_runtime_update()
            -> dpcm_be_disconnect()
                -> kfree(dpcm);
Thread 2:
    dpcm_fe_dai_trigger()
        -> dpcm_be_dai_trigger()
            -> snd_soc_dpcm_can_be_free_stop()
                -> if (dpcm->fe == fe)

Excpetion Scenario:
	two FE link to same BE
	FE1 -> BE
	FE2 ->

	Thread 1: switch of mixer between FE2 -> BE
	Thread 2: pcm_stop FE1

Exception:

Unable to handle kernel paging request at virtual address dead0000000000e0

pc=<> [<ffffff8960e2cd10>] dpcm_be_dai_trigger+0x29c/0x47c
	sound/soc/soc-pcm.c:3226
		if (dpcm->fe == fe)
lr=<> [<ffffff8960e2f694>] dpcm_fe_dai_do_trigger+0x94/0x26c

Backtrace:
[<ffffff89602dba80>] notify_die+0x68/0xb8
[<ffffff896028c7dc>] die+0x118/0x2a8
[<ffffff89602a2f84>] __do_kernel_fault+0x13c/0x14c
[<ffffff89602a27f4>] do_translation_fault+0x64/0xa0
[<ffffff8960280cf8>] do_mem_abort+0x4c/0xd0
[<ffffff8960282ad0>] el1_da+0x24/0x40
[<ffffff8960e2cd10>] dpcm_be_dai_trigger+0x29c/0x47c
[<ffffff8960e2f694>] dpcm_fe_dai_do_trigger+0x94/0x26c
[<ffffff8960e2edec>] dpcm_fe_dai_trigger+0x3c/0x44
[<ffffff8960de5588>] snd_pcm_do_stop+0x50/0x5c
[<ffffff8960dded24>] snd_pcm_action+0xb4/0x13c
[<ffffff8960ddfdb4>] snd_pcm_drop+0xa0/0x128
[<ffffff8960de69bc>] snd_pcm_common_ioctl+0x9d8/0x30f0
[<ffffff8960de1cac>] snd_pcm_ioctl_compat+0x29c/0x2f14
[<ffffff89604c9d60>] compat_SyS_ioctl+0x128/0x244
[<ffffff8960283740>] el0_svc_naked+0x34/0x38
[<ffffffffffffffff>] 0xffffffffffffffff

Signed-off-by: KaiChieh Chuang <kaichieh.chuang@mediatek.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
2019-03-18 11:19:00 +00:00
..
acpi
asm-generic kbuild: force all architectures except um to include mandatory-y 2019-03-17 12:56:32 +09:00
clocksource
crypto
drm drm i915, amdgpu, qxl and etnaviv fixes 2019-03-15 13:58:35 -07:00
dt-bindings We have a fairly balanced mix of clk driver updates and clk framework 2019-03-14 08:46:17 -07:00
keys Merge branch 'next-integrity' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-03-10 17:32:04 -07:00
kvm ARM: some cleanups, direct physical timer assignment, cache sanitization 2019-03-15 15:00:28 -07:00
linux pidfd patches for v5.1-rc1 2019-03-16 13:47:14 -07:00
math-emu
media
memory
misc
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-03-14 09:28:12 -07:00
pcmcia
ras
rdma
scsi
soc IOMMU Updates for Linux v5.1 2019-03-10 12:29:52 -07:00
sound ASoC: dpcm: prevent snd_soc_dpcm use after free 2019-03-18 11:19:00 +00:00
target
trace NFS client bugfixes for Linux 5.1 2019-03-16 12:28:18 -07:00
uapi Kbuild updates for v5.1 (2nd) 2019-03-17 13:25:26 -07:00
video media updates for v5.1-rc1 2019-03-09 14:45:54 -08:00
xen