Thanks Chaitanya for the detailed report. Dan Carpenter also reported a Smatch warning for this: https://lore.kernel.org/linux-mm/38ed0627-1283-4da2-827a-e90484d7bd7d@moroto.mountain/ The below should fix the problem, will respin the series to include the fix. --- diff --git a/mm/mmu_notifier.c b/mm/mmu_notifier.c index 63c8eb740af7..ec3b068cbbe6 100644 --- a/mm/mmu_notifier.c +++ b/mm/mmu_notifier.c @@ -621,9 +621,10 @@ int __mmu_notifier_register(struct mmu_notifier *subscription, * Subsystems should only register for invalidate_secondary_tlbs() or * invalidate_range_start()/end() callbacks, not both. */ - if (WARN_ON_ONCE(subscription->ops->arch_invalidate_secondary_tlbs && - (subscription->ops->invalidate_range_start || - subscription->ops->invalidate_range_end))) + if (WARN_ON_ONCE(subscription && + (subscription->ops->arch_invalidate_secondary_tlbs && + (subscription->ops->invalidate_range_start || + subscription->ops->invalidate_range_end)))) return -EINVAL; if (!mm->notifier_subscriptions) { "Borah, Chaitanya Kumar" <chaitanya.kumar.borah@xxxxxxxxx> writes: > Hello Alistair, > > Hope you are doing well. I am Chaitanya from the linux graphics team in Intel. > > This mail is regarding a regression we are seeing in our CI runs[1] on linux-next > repository. > > On next-20230720 [2], we are seeing the following error > > <4>[ 76.189375] Hardware name: Intel Corporation Meteor Lake Client Platform/MTL-P DDR5 SODIMM SBS RVP, BIOS MTLPFWI1.R00.3271.D81.2307101805 07/10/2023 > <4>[ 76.202534] RIP: 0010:__mmu_notifier_register+0x40/0x210 > <4>[ 76.207804] Code: 1a 71 5a 01 85 c0 0f 85 ec 00 00 00 48 8b 85 30 > 01 00 00 48 85 c0 0f 84 04 01 00 00 8b 85 cc 00 00 00 85 c0 0f 8e bb > 01 00 00 <49> 8b 44 24 10 48 83 78 38 00 74 1a 48 83 78 28 00 74 0c 0f > 0b b8 > <4>[ 76.226368] RSP: 0018:ffffc900019d7ca8 EFLAGS: 00010202 > <4>[ 76.231549] RAX: 0000000000000001 RBX: 0000000000001000 RCX: 0000000000000001 > <4>[ 76.238613] RDX: 0000000000000000 RSI: ffffffff823ceb7b RDI: ffffffff823ee12d > <4>[ 76.245680] RBP: ffff888102ec9b40 R08: 00000000ffffffff R09: 0000000000000001 > <4>[ 76.252747] R10: 0000000000000001 R11: ffff8881157cd2c0 R12: 0000000000000000 > <4>[ 76.259811] R13: ffff888102ec9c70 R14: ffffffffa07de500 R15: ffff888102ec9ce0 > <4>[ 76.266875] FS: 00007fbcabe11c00(0000) GS:ffff88846ec00000(0000) knlGS:0000000000000000 > <4>[ 76.274884] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > <4>[ 76.280578] CR2: 0000000000000010 CR3: 000000010d4c2005 CR4: 0000000000f70ee0 > <4>[ 76.287643] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > <4>[ 76.294711] DR3: 0000000000000000 DR6: 00000000ffff07f0 DR7: 0000000000000400 > <4>[ 76.301775] PKRU: 55555554 > <4>[ 76.304463] Call Trace: > <4>[ 76.306893] <TASK> > <4>[ 76.308983] ? __die_body+0x1a/0x60 > <4>[ 76.312444] ? page_fault_oops+0x156/0x450 > <4>[ 76.316510] ? do_user_addr_fault+0x65/0x980 > <4>[ 76.320747] ? exc_page_fault+0x68/0x1a0 > <4>[ 76.324643] ? asm_exc_page_fault+0x26/0x30 > <4>[ 76.328796] ? __mmu_notifier_register+0x40/0x210 > <4>[ 76.333460] ? __mmu_notifier_register+0x11c/0x210 > <4>[ 76.338206] ? preempt_count_add+0x4c/0xa0 > <4>[ 76.342273] mmu_notifier_register+0x30/0xe0 > <4>[ 76.346509] mmu_interval_notifier_insert+0x74/0xb0 > <4>[ 76.351344] i915_gem_userptr_ioctl+0x21a/0x320 [i915] > <4>[ 76.356565] ? __pfx_i915_gem_userptr_ioctl+0x10/0x10 [i915] > <4>[ 76.362271] drm_ioctl_kernel+0xb4/0x150 > <4>[ 76.366159] drm_ioctl+0x21d/0x420 > <4>[ 76.369537] ? __pfx_i915_gem_userptr_ioctl+0x10/0x10 [i915] > <4>[ 76.375242] ? find_held_lock+0x2b/0x80 > <4>[ 76.379046] __x64_sys_ioctl+0x79/0xb0 > <4>[ 76.382766] do_syscall_64+0x3c/0x90 > <4>[ 76.386312] entry_SYSCALL_64_after_hwframe+0x6e/0xd8 > <4>[ 76.391317] RIP: 0033:0x7fbcae63f3ab > > Details log can be found in [3]. > > After bisecting the tree, the following patch seems to be causing the > regression. > > commit 828fe4085cae77acb3abf7dd3d25b3ed6c560edf > Author: Alistair Popple apopple@xxxxxxxxxx > Date: Wed Jul 19 22:18:46 2023 +1000 > > mmu_notifiers: rename invalidate_range notifier > > There are two main use cases for mmu notifiers. One is by KVM which uses > mmu_notifier_invalidate_range_start()/end() to manage a software TLB. > > The other is to manage hardware TLBs which need to use the > invalidate_range() callback because HW can establish new TLB entries at > any time. Hence using start/end() can lead to memory corruption as these > callbacks happen too soon/late during page unmap. > > mmu notifier users should therefore either use the start()/end() callbacks > or the invalidate_range() callbacks. To make this usage clearer rename > the invalidate_range() callback to arch_invalidate_secondary_tlbs() and > update documention. > > Link: https://lkml.kernel.org/r/9a02dde2f8ddaad2db31e54706a80c12d1817aaf.1689768831.git-series.apopple@xxxxxxxxxx > > > We also verified by reverting the patch in the tree. > > Could you please check why this patch causes the regression and if we can find > a solution for it soon? > > [1] https://intel-gfx-ci.01.org/tree/linux-next/combined-alt.html? > [2] https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/commit/?h=next-20230720 > [3] https://intel-gfx-ci.01.org/tree/linux-next/next-20230720/bat-mtlp-6/dmesg0.txt
