Hi Chris, -----Original Message----- From: dri-devel <dri-devel-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of Chris Wilson Sent: Monday, February 15, 2021 6:10 PM To: Auld, Matthew <matthew.auld@xxxxxxxxx>; Ram Moon, AnandX <anandx.ram.moon@xxxxxxxxx>; Surendrakumar Upadhyay, TejaskumarX <tejaskumarx.surendrakumar.upadhyay@xxxxxxxxx>; Ursulin, Tvrtko <tvrtko.ursulin@xxxxxxxxx>; Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>; dri-devel@xxxxxxxxxxxxxxxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx Subject: Re: [Intel-gfx] [PATCH] drm/i915/gem: Add a check for object size for corner cases Quoting Ram Moon, AnandX (2021-02-15 12:29:17) > Hi Chris, > > -----Original Message----- > From: dri-devel <dri-devel-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of > Chris Wilson > Sent: Wednesday, February 10, 2021 4:15 PM > To: Ram Moon, AnandX <anandx.ram.moon@xxxxxxxxx>; Jani Nikula > <jani.nikula@xxxxxxxxxxxxxxx>; Auld, Matthew <matthew.auld@xxxxxxxxx>; > Surendrakumar Upadhyay, TejaskumarX > <tejaskumarx.surendrakumar.upadhyay@xxxxxxxxx>; Ursulin, Tvrtko > <tvrtko.ursulin@xxxxxxxxx>; dri-devel@xxxxxxxxxxxxxxxxxxxxx; > intel-gfx@xxxxxxxxxxxxxxxxxxxxx > Cc: Ram Moon, AnandX <anandx.ram.moon@xxxxxxxxx> > Subject: Re: [Intel-gfx] [PATCH] drm/i915/gem: Add a check for object > size for corner cases > > Quoting Anand Moon (2021-02-10 07:59:29) > > Add check for object size to return appropriate error -E2BIG or > > -EINVAL to avoid WARM_ON and successful return for some testcase. > > No. You miss the point of having those warnings. We need to inspect the code to remove the last remaining "int pagenum", and then we can remove the GEM_WARN_ON((sz) >> PAGE_SHIFT > INT_MAX). These are not emitted for users, only for us to motivate us into finally fixing the code. > -Chris > > Yes, I got your point these check are meant to catch up integer overflow. > > I have check with the IGT testcase case _gem_create_ and > _gem_userptr_blits_ which fails pass size *-1ull << 32* left shift > and *0~* which leads to integer overflow ie _negative_ size passed to create i915_gem_create via ioctl this leads to GM_WARN_ON. > > Can we drop these testcase so that we don't break the kernel ? The kernel rejects the ioctl with the expected errno. We leave a warning purely for the benefit of CI, only when compiled for debugging and not by default, so that we have a persistent reminder to do the code review. What's broken? -Chris All though the testcase return with appropriate error we observe kernel taint see below. Thanks -Anand IGT-Version: 1.25-g2982c998a (x86_64) (Linux: 5.11.0-rc7-CI-CI_DRM_9755+ x86_64) Starting subtest: create-massive Subtest create-massive: SUCCESS (0.001s) Err Starting subtest: create-massive Subtest create-massive: SUCCESS (0.001s) Dmesg Scroll to first warning <6> [245.057395] Console: switching to colour dummy device 80x25 <6> [245.057684] [IGT] gem_create: executing <6> [245.062015] [IGT] gem_create: starting subtest create-massive <4> [245.062063] ------------[ cut here ]------------ <4> [245.062065] WARN_ON((size) >> 12 > ((int)(~0U >> 1))) <4> [245.062089] WARNING: CPU: 1 PID: 1414 at drivers/gpu/drm/i915/gem/i915_gem_object.h:36 i915_gem_object_create_region+0x132/0x1b0 [i915] <4> [245.062196] Modules linked in: vgem snd_hda_codec_hdmi i915 mei_hdcp x86_pkg_temp_thermal coretemp crct10dif_pclmul crc32_pclmul snd_hda_intel snd_intel_dspcfg snd_hda_codec snd_hwdep snd_hda_core ghash_clmulni_intel cdc_ether usbnet snd_pcm mii e1000e ptp mei_me pps_core mei intel_lpss_pci prime_numbers <4> [245.062233] CPU: 1 PID: 1414 Comm: gem_create Tainted: G U 5.11.0-rc7-CI-CI_DRM_9755+ #1 <4> [245.062236] Hardware name: Intel Corporation Tiger Lake Client Platform/TigerLake U DDR4 SODIMM RVP, BIOS TGLSFWI1.R00.3197.A00.2005110542 05/11/2020 <4> [245.062238] RIP: 0010:i915_gem_object_create_region+0x132/0x1b0 [i915] <4> [245.062313] Code: 65 ff 0d 21 1c d5 5f 0f 85 79 ff ff ff e8 05 c7 d3 e0 e9 6f ff ff ff 48 c7 c6 70 6d 4e a0 48 c7 c7 0f fc 51 a0 e8 d7 4d 78 e1 <0f> 0b 49 c7 c4 f9 ff ff ff e9 65 ff ff ff 65 ff 05 e9 1b d5 5f 48 <4> [245.062315] RSP: 0018:ffffc9000230fd68 EFLAGS: 00010286 <4> [245.062319] RAX: 0000000000000000 RBX: ffffffff00000000 RCX: 0000000000000001 <4> [245.062320] RDX: 0000000080000001 RSI: ffffffff8235aaf7 RDI: 00000000ffffffff <4> [245.062322] RBP: ffff88812922a800 R08: 0000000000000001 R09: 0000000000000001 <4> [245.062324] R10: 0000000000000001 R11: 0000000000000000 R12: ffff88811a8bb400 <4> [245.062325] R13: 0000000000000000 R14: ffffc9000230fe58 R15: ffffc9000230fe58 <4> [245.062327] FS: 00007f7fbd88c300(0000) GS:ffff8884a0280000(0000) knlGS:0000000000000000 <4> [245.062329] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 <4> [245.062331] CR2: 00007f7fbd262be0 CR3: 00000001240b2001 CR4: 0000000000770ee0 <4> [245.062332] PKRU: 55555554 <4> [245.062334] Call Trace: <4> [245.062338] i915_gem_create+0xc4/0x160 [i915] <4> [245.062411] ? i915_gem_dumb_create+0xc0/0xc0 [i915] <4> [245.062591] drm_ioctl_kernel+0xaa/0xf0 <4> [245.062600] drm_ioctl+0x1e8/0x390 <4> [245.062604] ? i915_gem_dumb_create+0xc0/0xc0 [i915] _______________________________________________ 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
