e87581fe05
If usb_ep_autoconfig() fails (i.e. returns a null endpoint descriptor),
we expect afunc_bind() to fail (i.e. return a negative error code).
However, due to v4.10-rc1 commit f1d3861d63a5 ("usb: gadget: f_uac2: fix
error handling at afunc_bind"), afunc_bind() returns zero, telling the
caller that it succeeded. This then generates NULL pointer dereference
in below scenario on Rcar H3-ES20-Salvator-X target:
rcar-gen3:/home/root# modprobe g_audio
[ 626.521155] g_audio gadget: afunc_bind:565 Error!
[ 626.526319] g_audio gadget: Linux USB Audio Gadget, version: Feb 2, 2012
[ 626.533405] g_audio gadget: g_audio ready
rcar-gen3:/home/root#
rcar-gen3:/home/root# modprobe -r g_audio
[ 728.256707] ==================================================================
[ 728.264293] BUG: KASAN: null-ptr-deref in u_audio_stop_capture+0x70/0x268 [u_audio]
[ 728.272244] Read of size 8 at addr 00000000000000a0 by task modprobe/2545
[ 728.279309]
[ 728.280849] CPU: 0 PID: 2545 Comm: modprobe Tainted: G WC 4.14.47+ #152
[ 728.288778] Hardware name: Renesas Salvator-X board based on r8a7795 ES2.0+ (DT)
[ 728.296454] Call trace:
[ 728.299151] [<ffff2000080925ac>] dump_backtrace+0x0/0x364
[ 728.304808] [<ffff200008092924>] show_stack+0x14/0x1c
[ 728.310081] [<ffff200008f8d5cc>] dump_stack+0x108/0x174
[ 728.315522] [<ffff2000083c77c8>] kasan_report+0x1fc/0x354
[ 728.321134] [<ffff2000083c611c>] __asan_load8+0x24/0x94
[ 728.326600] [<ffff2000021e1618>] u_audio_stop_capture+0x70/0x268 [u_audio]
[ 728.333735] [<ffff2000021f8b7c>] afunc_disable+0x44/0x60 [usb_f_uac2]
[ 728.340503] [<ffff20000218177c>] usb_remove_function+0x9c/0x210 [libcomposite]
[ 728.348060] [<ffff200002183320>] remove_config.isra.2+0x1d8/0x218 [libcomposite]
[ 728.355788] [<ffff200002186c54>] __composite_unbind+0x104/0x1f8 [libcomposite]
[ 728.363339] [<ffff200002186d58>] composite_unbind+0x10/0x18 [libcomposite]
[ 728.370536] [<ffff20000152f158>] usb_gadget_remove_driver+0xc0/0x170 [udc_core]
[ 728.378172] [<ffff20000153154c>] usb_gadget_unregister_driver+0x1cc/0x258 [udc_core]
[ 728.386274] [<ffff200002180de8>] usb_composite_unregister+0x10/0x18 [libcomposite]
[ 728.394116] [<ffff2000021d035c>] audio_driver_exit+0x14/0x28 [g_audio]
[ 728.400878] [<ffff200008213ed4>] SyS_delete_module+0x288/0x32c
[ 728.406935] Exception stack(0xffff8006cf6c7ec0 to 0xffff8006cf6c8000)
[ 728.413624] 7ec0: 0000000006136428 0000000000000800 0000000000000000 0000ffffd706efe8
[ 728.421718] 7ee0: 0000ffffd706efe9 000000000000000a 1999999999999999 0000000000000000
[ 728.429792] 7f00: 000000000000006a 000000000042c078 0000000000000000 0000000000000005
[ 728.437870] 7f20: 0000000000000000 0000000000000000 0000000000000004 0000000000000000
[ 728.445952] 7f40: 000000000042bfc8 0000ffffbc7c8f40 0000000000000000 00000000061363c0
[ 728.454035] 7f60: 0000000006136428 0000000000000000 0000000000000000 0000000006136428
[ 728.462114] 7f80: 000000000042c000 0000ffffd7071448 000000000042c000 0000000000000000
[ 728.470190] 7fa0: 00000000061350c0 0000ffffd7070010 000000000041129c 0000ffffd7070010
[ 728.478281] 7fc0: 0000ffffbc7c8f48 0000000060000000 0000000006136428 000000000000006a
[ 728.486351] 7fe0: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[ 728.494434] [<ffff200008084780>] el0_svc_naked+0x34/0x38
[ 728.499957] ==================================================================
[ 728.507801] Unable to handle kernel NULL pointer dereference at virtual address 000000a0
[ 728.517742] Mem abort info:
[ 728.520993] Exception class = DABT (current EL), IL = 32 bits
[ 728.527375] SET = 0, FnV = 0
[ 728.530731] EA = 0, S1PTW = 0
[ 728.534361] Data abort info:
[ 728.537650] ISV = 0, ISS = 0x00000006
[ 728.541863] CM = 0, WnR = 0
[ 728.545167] user pgtable: 4k pages, 48-bit VAs, pgd = ffff8006c6100000
[ 728.552156] [00000000000000a0] *pgd=0000000716a8d003
[ 728.557519] , *pud=00000007116fc003
[ 728.561259] , *pmd=0000000000000000
[ 728.564985] Internal error: Oops: 96000006 [#1] PREEMPT SMP
[ 728.570815] Modules linked in:
[ 728.574023] usb_f_uac2
[ 728.576560] u_audio
[ 728.578827] g_audio(-)
[ 728.581361] libcomposite
[ 728.584071] configfs
[ 728.586428] aes_ce_blk
[ 728.588960] sata_rcar
[ 728.591421] crypto_simd
[ 728.594039] cryptd
[ 728.596217] libata
[ 728.598396] aes_ce_cipher
[ 728.601188] crc32_ce
[ 728.603542] ghash_ce
[ 728.605896] gf128mul
[ 728.608250] aes_arm64
[ 728.610692] scsi_mod
[ 728.613046] sha2_ce
[ 728.615313] xhci_plat_hcd
[ 728.618106] sha256_arm64
[ 728.620811] sha1_ce
[ 728.623077] renesas_usbhs
[ 728.625869] xhci_hcd
[ 728.628243] renesas_usb3
[ 728.630948] sha1_generic
[ 728.633670] ravb_streaming(C)
[ 728.636814] udc_core
[ 728.639168] cpufreq_dt
[ 728.641697] rcar_gen3_thermal
[ 728.644840] usb_dmac
[ 728.647194] pwm_rcar
[ 728.649548] thermal_sys
[ 728.652165] virt_dma
[ 728.654519] mch_core(C)
[ 728.657137] pwm_bl
[ 728.659315] snd_soc_rcar
[ 728.662020] snd_aloop
[ 728.664462] snd_soc_generic_card
[ 728.667869] snd_soc_ak4613
[ 728.670749] ipv6
[ 728.672768] autofs4
[ 728.675052] CPU: 0 PID: 2545 Comm: modprobe Tainted: G B WC 4.14.47+ #152
[ 728.682973] Hardware name: Renesas Salvator-X board based on r8a7795 ES2.0+ (DT)
[ 728.690637] task: ffff8006ced38000 task.stack: ffff8006cf6c0000
[ 728.696814] PC is at u_audio_stop_capture+0x70/0x268 [u_audio]
[ 728.702896] LR is at u_audio_stop_capture+0x70/0x268 [u_audio]
[ 728.708964] pc : [<ffff2000021e1618>] lr : [<ffff2000021e1618>] pstate: 60000145
[ 728.716620] sp : ffff8006cf6c7a50
[ 728.720154] x29: ffff8006cf6c7a50
[ 728.723760] x28: ffff8006ced38000
[ 728.727272] x27: ffff200008fd7000
[ 728.730857] x26: ffff2000021d2340
[ 728.734361] x25: 0000000000000000
[ 728.737948] x24: ffff200009e94b08
[ 728.741452] x23: 00000000000000a0
[ 728.745052] x22: 00000000000000a8
[ 728.748558] x21: 1ffff000d9ed8f7c
[ 728.752142] x20: ffff8006d671a800
[ 728.755646] x19: 0000000000000000
[ 728.759231] x18: 0000000000000000
[ 728.762736] x17: 0000ffffbc7c8f40
[ 728.766320] x16: ffff200008213c4c
[ 728.769823] x15: 0000000000000000
[ 728.773408] x14: 0720072007200720
[ 728.776912] x13: 0720072007200720
[ 728.780497] x12: ffffffffffffffff
[ 728.784001] x11: 0000000000000040
[ 728.787598] x10: 0000000000001600
[ 728.791103] x9 : ffff8006cf6c77a0
[ 728.794689] x8 : ffff8006ced39660
[ 728.798193] x7 : ffff20000811c738
[ 728.801794] x6 : 0000000000000000
[ 728.805299] x5 : dfff200000000000
[ 728.808885] x4 : ffff8006ced38000
[ 728.812390] x3 : ffff200008fb46e8
[ 728.815976] x2 : 0000000000000007
[ 728.819480] x1 : 3ba68643e7431500
[ 728.823066] x0 : 0000000000000000
[ 728.826574] Process modprobe (pid: 2545, stack limit = 0xffff8006cf6c0000)
[ 728.833704] Call trace:
[ 728.836292] Exception stack(0xffff8006cf6c7910 to 0xffff8006cf6c7a50)
[ 728.842987] 7900: 0000000000000000 3ba68643e7431500
[ 728.851084] 7920: 0000000000000007 ffff200008fb46e8 ffff8006ced38000 dfff200000000000
[ 728.859173] 7940: 0000000000000000 ffff20000811c738 ffff8006ced39660 ffff8006cf6c77a0
[ 728.867248] 7960: 0000000000001600 0000000000000040 ffffffffffffffff 0720072007200720
[ 728.875323] 7980: 0720072007200720 0000000000000000 ffff200008213c4c 0000ffffbc7c8f40
[ 728.883412] 79a0: 0000000000000000 0000000000000000 ffff8006d671a800 1ffff000d9ed8f7c
[ 728.891485] 79c0: 00000000000000a8 00000000000000a0 ffff200009e94b08 0000000000000000
[ 728.899561] 79e0: ffff2000021d2340 ffff200008fd7000 ffff8006ced38000 ffff8006cf6c7a50
[ 728.907636] 7a00: ffff2000021e1618 ffff8006cf6c7a50 ffff2000021e1618 0000000060000145
[ 728.915710] 7a20: 0000000000000008 0000000000000000 0000ffffffffffff 3ba68643e7431500
[ 728.923780] 7a40: ffff8006cf6c7a50 ffff2000021e1618
[ 728.928880] [<ffff2000021e1618>] u_audio_stop_capture+0x70/0x268 [u_audio]
[ 728.936032] [<ffff2000021f8b7c>] afunc_disable+0x44/0x60 [usb_f_uac2]
[ 728.942822] [<ffff20000218177c>] usb_remove_function+0x9c/0x210 [libcomposite]
[ 728.950385] [<ffff200002183320>] remove_config.isra.2+0x1d8/0x218 [libcomposite]
[ 728.958134] [<ffff200002186c54>] __composite_unbind+0x104/0x1f8 [libcomposite]
[ 728.965689] [<ffff200002186d58>] composite_unbind+0x10/0x18 [libcomposite]
[ 728.972882] [<ffff20000152f158>] usb_gadget_remove_driver+0xc0/0x170 [udc_core]
[ 728.980522] [<ffff20000153154c>] usb_gadget_unregister_driver+0x1cc/0x258 [udc_core]
[ 728.988638] [<ffff200002180de8>] usb_composite_unregister+0x10/0x18 [libcomposite]
[ 728.996472] [<ffff2000021d035c>] audio_driver_exit+0x14/0x28 [g_audio]
[ 729.003231] [<ffff200008213ed4>] SyS_delete_module+0x288/0x32c
[ 729.009278] Exception stack(0xffff8006cf6c7ec0 to 0xffff8006cf6c8000)
[ 729.015946] 7ec0: 0000000006136428 0000000000000800 0000000000000000 0000ffffd706efe8
[ 729.024022] 7ee0: 0000ffffd706efe9 000000000000000a 1999999999999999 0000000000000000
[ 729.032099] 7f00: 000000000000006a 000000000042c078 0000000000000000 0000000000000005
[ 729.040172] 7f20: 0000000000000000 0000000000000000 0000000000000004 0000000000000000
[ 729.048263] 7f40: 000000000042bfc8 0000ffffbc7c8f40 0000000000000000 00000000061363c0
[ 729.056337] 7f60: 0000000006136428 0000000000000000 0000000000000000 0000000006136428
[ 729.064411] 7f80: 000000000042c000 0000ffffd7071448 000000000042c000 0000000000000000
[ 729.072484] 7fa0: 00000000061350c0 0000ffffd7070010 000000000041129c 0000ffffd7070010
[ 729.080563] 7fc0: 0000ffffbc7c8f48 0000000060000000 0000000006136428 000000000000006a
[ 729.088636] 7fe0: 0000000000000000 0000000000000000 0000000000000000 0000000000000000
[ 729.096733] [<ffff200008084780>] el0_svc_naked+0x34/0x38
[ 729.102259] Code: 9597d1b3 aa1703e0 9102a276 958792b9 (f9405275)
[ 729.108617] ---[ end trace 7560c5fa3d100243 ]---
After this patch is applied, the issue is fixed:
rcar-gen3:/home/root# modprobe g_audio
[ 59.217127] g_audio gadget: afunc_bind:565 Error!
[ 59.222329] g_audio ee020000.usb: failed to start g_audio: -19
modprobe: ERROR: could not insert 'g_audio': No such device
rcar-gen3:/home/root# modprobe -r g_audio
rcar-gen3:/home/root#
Fixes: f1d3861d63a5 ("usb: gadget: f_uac2: fix error handling at afunc_bind")
Signed-off-by: Eugeniu Rosca <erosca@de.adit-jv.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.