| Message ID | 1441794592-2775-1-git-send-email-michel.thierry@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wed, Sep 09, 2015 at 11:29:52AM +0100, Michel Thierry wrote: > i915_gem_object_bind_to_vm returns -E2BIG when the user tries to bind an > object larger than the aperture, but i915_gem_fault does not handle this > return code: > > [501906.530985] gem_mmap_gtt: starting subtest big-bo-tiledX > [501906.541992] gem_mmap_gtt (22362): drop_caches: 3 > [501906.610774] WARNING: CPU: 2 PID: 22362 at > drivers/gpu/drm/i915/i915_gem.c:1880 i915_gem_fault+0x24f/0x470 [i915]() > [501906.623568] unhandled error in i915_gem_fault: -7 > [501906.825115] Call Trace: > [501906.830322] [<ffffffff8178ffcc>] dump_stack+0x45/0x57 > [501906.838589] [<ffffffff810759aa>] warn_slowpath_common+0x8a/0xc0 > [501906.847846] [<ffffffff81075a26>] warn_slowpath_fmt+0x46/0x50 > [501906.856776] [<ffffffffc079591f>] i915_gem_fault+0x24f/0x470 [i915] > [501906.866276] [<ffffffff8119e11d>] __do_fault+0x3d/0xa0 > [501906.874464] [<ffffffff81068cc0>] ? pte_alloc_one+0x30/0x50 > [501906.883169] [<ffffffff811a26a7>] handle_mm_fault+0xe27/0x1810 > [501906.892202] [<ffffffff81306e8a>] ? security_mmap_file+0xca/0xe0 > [501906.900389] [<ffffffff811fb6ad>] ? do_vfs_ioctl+0x2cd/0x4b0 > [501906.908143] [<ffffffff81063ada>] __do_page_fault+0x19a/0x430 > [501906.916024] [<ffffffff81063d92>] do_page_fault+0x22/0x30 > [501906.923532] [<ffffffff81799248>] page_fault+0x28/0x30 > > RFC about the error code that should be returned by i915_gem_fault. There are two fixes here, change E2BIG to ENOSPC. The differentiate is painful to all consumers (and missing in userspace). The second is that gem_fault was supposed to be fixed to handle it and sigbus is the legimate error for that case (not enomem/sigsegv). -Chris
On 9/9/2015 11:33 AM, Chris Wilson wrote: > On Wed, Sep 09, 2015 at 11:29:52AM +0100, Michel Thierry wrote: >> i915_gem_object_bind_to_vm returns -E2BIG when the user tries to bind an >> object larger than the aperture, but i915_gem_fault does not handle this >> return code: >> >> [501906.530985] gem_mmap_gtt: starting subtest big-bo-tiledX >> [501906.541992] gem_mmap_gtt (22362): drop_caches: 3 >> [501906.610774] WARNING: CPU: 2 PID: 22362 at >> drivers/gpu/drm/i915/i915_gem.c:1880 i915_gem_fault+0x24f/0x470 [i915]() >> [501906.623568] unhandled error in i915_gem_fault: -7 >> [501906.825115] Call Trace: >> [501906.830322] [<ffffffff8178ffcc>] dump_stack+0x45/0x57 >> [501906.838589] [<ffffffff810759aa>] warn_slowpath_common+0x8a/0xc0 >> [501906.847846] [<ffffffff81075a26>] warn_slowpath_fmt+0x46/0x50 >> [501906.856776] [<ffffffffc079591f>] i915_gem_fault+0x24f/0x470 [i915] >> [501906.866276] [<ffffffff8119e11d>] __do_fault+0x3d/0xa0 >> [501906.874464] [<ffffffff81068cc0>] ? pte_alloc_one+0x30/0x50 >> [501906.883169] [<ffffffff811a26a7>] handle_mm_fault+0xe27/0x1810 >> [501906.892202] [<ffffffff81306e8a>] ? security_mmap_file+0xca/0xe0 >> [501906.900389] [<ffffffff811fb6ad>] ? do_vfs_ioctl+0x2cd/0x4b0 >> [501906.908143] [<ffffffff81063ada>] __do_page_fault+0x19a/0x430 >> [501906.916024] [<ffffffff81063d92>] do_page_fault+0x22/0x30 >> [501906.923532] [<ffffffff81799248>] page_fault+0x28/0x30 >> >> RFC about the error code that should be returned by i915_gem_fault. > > There are two fixes here, change E2BIG to ENOSPC. The differentiate is > painful to all consumers (and missing in userspace). I'll change the return code in gem_object_bind_to_vm instead. > > The second is that gem_fault was supposed to be fixed to handle it and > sigbus is the legimate error for that case (not enomem/sigsegv). These subtests use objs tiling x/y, so the driver won't use partial views. Should it be better if i915_gem_mmap_gtt checks for this (obj size bigger than apperture and some tiling mode), and return an error at that point? Instead of waiting for the sigbus error in gem_fault. -Michel
On Wed, Sep 09, 2015 at 05:53:57PM +0100, Michel Thierry wrote: > On 9/9/2015 11:33 AM, Chris Wilson wrote: > >On Wed, Sep 09, 2015 at 11:29:52AM +0100, Michel Thierry wrote: > >>i915_gem_object_bind_to_vm returns -E2BIG when the user tries to bind an > >>object larger than the aperture, but i915_gem_fault does not handle this > >>return code: > >> > >>[501906.530985] gem_mmap_gtt: starting subtest big-bo-tiledX > >>[501906.541992] gem_mmap_gtt (22362): drop_caches: 3 > >>[501906.610774] WARNING: CPU: 2 PID: 22362 at > >>drivers/gpu/drm/i915/i915_gem.c:1880 i915_gem_fault+0x24f/0x470 [i915]() > >>[501906.623568] unhandled error in i915_gem_fault: -7 > >>[501906.825115] Call Trace: > >>[501906.830322] [<ffffffff8178ffcc>] dump_stack+0x45/0x57 > >>[501906.838589] [<ffffffff810759aa>] warn_slowpath_common+0x8a/0xc0 > >>[501906.847846] [<ffffffff81075a26>] warn_slowpath_fmt+0x46/0x50 > >>[501906.856776] [<ffffffffc079591f>] i915_gem_fault+0x24f/0x470 [i915] > >>[501906.866276] [<ffffffff8119e11d>] __do_fault+0x3d/0xa0 > >>[501906.874464] [<ffffffff81068cc0>] ? pte_alloc_one+0x30/0x50 > >>[501906.883169] [<ffffffff811a26a7>] handle_mm_fault+0xe27/0x1810 > >>[501906.892202] [<ffffffff81306e8a>] ? security_mmap_file+0xca/0xe0 > >>[501906.900389] [<ffffffff811fb6ad>] ? do_vfs_ioctl+0x2cd/0x4b0 > >>[501906.908143] [<ffffffff81063ada>] __do_page_fault+0x19a/0x430 > >>[501906.916024] [<ffffffff81063d92>] do_page_fault+0x22/0x30 > >>[501906.923532] [<ffffffff81799248>] page_fault+0x28/0x30 > >> > >>RFC about the error code that should be returned by i915_gem_fault. > > > >There are two fixes here, change E2BIG to ENOSPC. The differentiate is > >painful to all consumers (and missing in userspace). > > I'll change the return code in gem_object_bind_to_vm instead. > > > > >The second is that gem_fault was supposed to be fixed to handle it and > >sigbus is the legimate error for that case (not enomem/sigsegv). > > These subtests use objs tiling x/y, so the driver won't use partial views. > > Should it be better if i915_gem_mmap_gtt checks for this (obj size > bigger than apperture and some tiling mode), and return an error at > that point? Instead of waiting for the sigbus error in gem_fault. No, the driver is meant to use a partial fenced view in this case. The feature was merged very early and is still very, very incomplete. -Chris
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 352ccd5..3e00f72 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1869,6 +1869,7 @@ out: */ ret = VM_FAULT_NOPAGE; break; + case -E2BIG: case -ENOMEM: ret = VM_FAULT_OOM; break;
i915_gem_object_bind_to_vm returns -E2BIG when the user tries to bind an object larger than the aperture, but i915_gem_fault does not handle this return code: [501906.530985] gem_mmap_gtt: starting subtest big-bo-tiledX [501906.541992] gem_mmap_gtt (22362): drop_caches: 3 [501906.610774] WARNING: CPU: 2 PID: 22362 at drivers/gpu/drm/i915/i915_gem.c:1880 i915_gem_fault+0x24f/0x470 [i915]() [501906.623568] unhandled error in i915_gem_fault: -7 [501906.825115] Call Trace: [501906.830322] [<ffffffff8178ffcc>] dump_stack+0x45/0x57 [501906.838589] [<ffffffff810759aa>] warn_slowpath_common+0x8a/0xc0 [501906.847846] [<ffffffff81075a26>] warn_slowpath_fmt+0x46/0x50 [501906.856776] [<ffffffffc079591f>] i915_gem_fault+0x24f/0x470 [i915] [501906.866276] [<ffffffff8119e11d>] __do_fault+0x3d/0xa0 [501906.874464] [<ffffffff81068cc0>] ? pte_alloc_one+0x30/0x50 [501906.883169] [<ffffffff811a26a7>] handle_mm_fault+0xe27/0x1810 [501906.892202] [<ffffffff81306e8a>] ? security_mmap_file+0xca/0xe0 [501906.900389] [<ffffffff811fb6ad>] ? do_vfs_ioctl+0x2cd/0x4b0 [501906.908143] [<ffffffff81063ada>] __do_page_fault+0x19a/0x430 [501906.916024] [<ffffffff81063d92>] do_page_fault+0x22/0x30 [501906.923532] [<ffffffff81799248>] page_fault+0x28/0x30 RFC about the error code that should be returned by i915_gem_fault. Testcase: igt/gem_mmap_gtt/big-bo-tiledXY Reported-by: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com> Signed-off-by: Michel Thierry <michel.thierry@intel.com> --- drivers/gpu/drm/i915/i915_gem.c | 1 + 1 file changed, 1 insertion(+)