On Tue, Mar 22, 2016 at 8:29 AM, Nicolai Stange <nicstange@xxxxxxxxx> wrote: > Alex Deucher <alexdeucher@xxxxxxxxx> writes: > >> On Mon, Mar 21, 2016 at 8:10 AM, Nicolai Stange <nicstange@xxxxxxxxx> wrote: >>> The values of all but the RADEON_HPD_NONE members of the radeon_hpd_id >>> enum transform 1:1 into bit positions within the 'enabled' bitset as >>> assembled by evergreen_hpd_init(): >>> >>> enabled |= 1 << radeon_connector->hpd.hpd; >>> >>> However, if ->hpd.hpd happens to equal RADEON_HPD_NONE == 0xff, UBSAN >>> reports >>> >>> UBSAN: Undefined behaviour in drivers/gpu/drm/radeon/evergreen.c:1867:16 >>> shift exponent 255 is too large for 32-bit type 'int' >>> [...] >>> Call Trace: >>> [<ffffffff818c4d35>] dump_stack+0xbc/0x117 >>> [<ffffffff818c4c79>] ? _atomic_dec_and_lock+0x169/0x169 >>> [<ffffffff819411bb>] ubsan_epilogue+0xd/0x4e >>> [<ffffffff81941cbc>] __ubsan_handle_shift_out_of_bounds+0x1fb/0x254 >>> [<ffffffffa0ba7f2e>] ? atom_execute_table+0x3e/0x50 [radeon] >>> [<ffffffff81941ac1>] ? __ubsan_handle_load_invalid_value+0x158/0x158 >>> [<ffffffffa0b87700>] ? radeon_get_pll_use_mask+0x130/0x130 [radeon] >>> [<ffffffff81219930>] ? wake_up_klogd_work_func+0x60/0x60 >>> [<ffffffff8121a35e>] ? vprintk_default+0x3e/0x60 >>> [<ffffffffa0c603c4>] evergreen_hpd_init+0x274/0x2d0 [radeon] >>> [<ffffffffa0c603c4>] ? evergreen_hpd_init+0x274/0x2d0 [radeon] >>> [<ffffffffa0bd196e>] radeon_modeset_init+0x8ce/0x18d0 [radeon] >>> [<ffffffffa0b71d86>] radeon_driver_load_kms+0x186/0x350 [radeon] >>> [<ffffffffa03b6b16>] drm_dev_register+0xc6/0x100 [drm] >>> [<ffffffffa03bc8c4>] drm_get_pci_dev+0xe4/0x490 [drm] >>> [<ffffffff814b83f0>] ? kfree+0x220/0x370 >>> [<ffffffffa0b687c2>] radeon_pci_probe+0x112/0x140 [radeon] >>> [...] >>> ===================================================================== >>> radeon 0000:01:00.0: No connectors reported connected with modes >>> >>> At least on x86, there should be no user-visible impact as there >>> >>> 1 << 0xff == 1 << (0xff & 31) == 1 << 31 >>> >>> holds and 31 > RADEON_MAX_HPD_PINS. Thus, this patch is a cosmetic one. >>> >>> All of the above applies analogously to evergreen_hpd_fini(). >>> >>> Silence UBSAN by checking ->hpd.hpd for RADEON_HPD_NONE before oring it >>> into the 'enabled' bitset in evergreen_hpd_init() or the 'disabled' bitset >>> in evergreen_hpd_fini() respectively. >>> >>> Signed-off-by: Nicolai Stange <nicstange@xxxxxxxxx> >> >> Can you please fix all instances of this? This same pattern is >> repeated in various asic families. > > Sure. > > The places to fix are: > $ git grep -n '1 *<<.*hpd' -- drivers/gpu/drm/radeon/ > drivers/gpu/drm/radeon/evergreen.c:1868: enabled |= 1 << radeon_connector->hpd.hpd; > drivers/gpu/drm/radeon/evergreen.c:1912: disabled |= 1 << radeon_connector->hpd.hpd; > drivers/gpu/drm/radeon/r100.c:595: enable |= 1 << radeon_connector->hpd.hpd; > drivers/gpu/drm/radeon/r100.c:617: disable |= 1 << radeon_connector->hpd.hpd; > drivers/gpu/drm/radeon/r600.c:1005: enable |= 1 << radeon_connector->hpd.hpd; > drivers/gpu/drm/radeon/r600.c:1058: disable |= 1 << radeon_connector->hpd.hpd; > drivers/gpu/drm/radeon/rs600.c:416: enable |= 1 << radeon_connector->hpd.hpd; > drivers/gpu/drm/radeon/rs600.c:442: disable |= 1 << radeon_connector->hpd.hpd; > > May I throw all of those into one single patch? Yes, that would be fine. Alex > > > Thanks, > > Nicolai > > >> >>> --- >>> Applicable to linux-next-20160321. >>> >>> Changes to v1: >>> - Turn commit message's impact part into a non-impact part. >>> >>> drivers/gpu/drm/radeon/evergreen.c | 6 ++++-- >>> 1 file changed, 4 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/gpu/drm/radeon/evergreen.c b/drivers/gpu/drm/radeon/evergreen.c >>> index 76c4bdf..6360717 100644 >>> --- a/drivers/gpu/drm/radeon/evergreen.c >>> +++ b/drivers/gpu/drm/radeon/evergreen.c >>> @@ -1864,7 +1864,8 @@ void evergreen_hpd_init(struct radeon_device *rdev) >>> break; >>> } >>> radeon_hpd_set_polarity(rdev, radeon_connector->hpd.hpd); >>> - enabled |= 1 << radeon_connector->hpd.hpd; >>> + if (radeon_connector->hpd.hpd != RADEON_HPD_NONE) >>> + enabled |= 1 << radeon_connector->hpd.hpd; >>> } >>> radeon_irq_kms_enable_hpd(rdev, enabled); >>> } >>> @@ -1907,7 +1908,8 @@ void evergreen_hpd_fini(struct radeon_device *rdev) >>> default: >>> break; >>> } >>> - disabled |= 1 << radeon_connector->hpd.hpd; >>> + if (radeon_connector->hpd.hpd != RADEON_HPD_NONE) >>> + disabled |= 1 << radeon_connector->hpd.hpd; >>> } >>> radeon_irq_kms_disable_hpd(rdev, disabled); >>> } >>> -- >>> 2.7.3 >>> >>> _______________________________________________ >>> dri-devel mailing list >>> dri-devel@xxxxxxxxxxxxxxxxxxxxx >>> https://lists.freedesktop.org/mailman/listinfo/dri-devel _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
