On Tue, Jan 03, 2023 at 09:46:33PM +0800, Oliver Sang wrote: > On Tue, Jan 03, 2023 at 11:42:11AM +0100, Vlastimil Babka wrote: > > So the events leading up to this could be something like: > > > > - 0x2daee is order-1 slab folio of the inode cache, sitting on the partial list > > - despite being on partial list, it's freed ??? > > - somebody else allocates order-2 page 0x2daec and uses it for whatever, > > then frees it > > - 0x2daec is reallocated as order-1 slab from names_cache, then freed > > - we try to allocate from the slab page 0x2daee and trip on the PageTail > > > > Except, the freeing of order-2 page would have reset the PageTail and > > compound_head in 0x2daec, so this is even more complicated or involves some > > extra race? > > FYI, we ran tests more up to 500 times, then saw different issues but rate is > actually low > > 56d5a2b9ba85a390 0af8489b0216fa1dd83e264bef8 > ---------------- --------------------------- > fail:runs %reproduction fail:runs > | | | > :500 12% 61:500 dmesg.invalid_opcode:#[##] > :500 3% 14:500 dmesg.kernel_BUG_at_include/linux/mm.h > :500 3% 17:500 dmesg.kernel_BUG_at_include/linux/page-flags.h > :500 5% 26:500 dmesg.kernel_BUG_at_lib/list_debug.c > :500 0% 2:500 dmesg.kernel_BUG_at_mm/page_alloc.c > :500 0% 2:500 dmesg.kernel_BUG_at_mm/usercopy.c > > > > > In any case, this is something a debug_pagealloc kernel could have a chance > > of catching earlier. Would it be possible to enable CONFIG_DEBUG_PAGEALLOC > > and DEBUG_PAGEALLOC_ENABLE_DEFAULT additionally to the rest of the > > configuration, and repeat the test? > > ok, we are starting to test by these 2 additional configs now. BTW it seems to be totally unrelated to rcutorture tests. Are there similar reports in boot tests with the same config? > > > > Separately we should also make the __dump_page() more resilient. > > > > Thanks, > > Vlastimil > > > > > [ 25.804432][ T214] ------------[ cut here ]------------ > > > [ 25.804917][ T214] kernel BUG at include/linux/mm.h:825! > > > [ 25.805402][ T214] invalid opcode: 0000 [#1] SMP > > > [ 25.805820][ T214] CPU: 0 PID: 214 Comm: udevadm Tainted: G S 6.1.0-rc2-00014-g0af8489b0216 #2 1c4d7707ec0ce574ed62a77e82a8580202758048 > > > [ 25.806944][ T214] EIP: __dump_page.cold+0x282/0x369 > > > [ 25.807376][ T214] Code: ff ff 83 05 e8 5d bb c5 01 ba 4c c4 2f c4 89 f8 83 15 ec 5d bb c5 00 e8 f2 92 ed fd 83 05 f8 5d bb c5 01 83 15 fc 5d bb c5 00 <0f> 0b 83 05 00 5e bb c5 01 b8 ac 85 a3 c4 83 15 04 5e bb c5 00 e8 > > > [ 25.808960][ T214] EAX: 00000000 EBX: e764d530 ECX: 00000003 EDX: 4108888f > > > [ 25.809578][ T214] ESI: e764d4e0 EDI: e764d4e0 EBP: ed89db3c ESP: ed89db00 > > > [ 25.810168][ T214] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 EFLAGS: 00210046 > > > [ 25.810803][ T214] CR0: 80050033 CR2: 00616abc CR3: 2d878000 CR4: 000406d0 > > > [ 25.811407][ T214] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 > > > [ 25.811999][ T214] DR6: fffe0ff0 DR7: 00000400 > > > [ 25.812390][ T214] Call Trace: > > > [ 25.812675][ T214] dump_page+0x2a/0xc0 > > > [ 25.813025][ T214] ? _raw_spin_lock_irqsave+0x16/0x30 > > > [ 25.813492][ T214] folio_flags+0x23/0x70 > > > [ 25.813945][ T214] get_partial_node+0x89/0x290 > > > [ 25.814357][ T214] __slab_alloc_node+0xbb/0x270 > > > [ 25.814860][ T214] kmem_cache_alloc_lru+0x8d/0x4e0 > > > [ 25.815289][ T214] ? __lock_release+0x3ec/0x410 > > > [ 25.815697][ T214] ? iget_locked+0x78/0x310 > > > [ 25.816096][ T214] alloc_inode+0x93/0x150 > > > [ 25.816469][ T214] iget_locked+0xdd/0x310 > > > [ 25.816829][ T214] ? lock_is_held_type+0x80/0xf0 > > > [ 25.817264][ T214] kernfs_get_inode+0x24/0xb0 > > > [ 25.817670][ T214] kernfs_iop_lookup+0xb5/0x1a0 > > > [ 25.818087][ T214] __lookup_slow+0xd9/0x2a0 > > > [ 25.818479][ T214] lookup_slow+0x50/0x90 > > > [ 25.818847][ T214] walk_component+0x19c/0x2c0 > > > [ 25.819244][ T214] path_lookupat+0xa3/0x270 > > > [ 25.819627][ T214] path_openat+0x307/0x3e0 > > > [ 25.820007][ T214] do_filp_open+0x7c/0x130 > > > [ 25.820409][ T214] do_sys_openat2+0x113/0x1f0 > > > [ 25.820807][ T214] do_sys_open+0x8e/0xe0 > > > [ 25.821211][ T214] __ia32_sys_openat+0x2b/0x40 > > > [ 25.821622][ T214] __do_fast_syscall_32+0x72/0xd0 > > > [ 25.822057][ T214] ? trace_hardirqs_on+0xa2/0x110 > > > [ 25.822480][ T214] ? __fput+0x19f/0x390 > > > [ 25.822842][ T214] ? lockdep_hardirqs_on_prepare+0x242/0x400 > > > [ 25.823346][ T214] ? syscall_exit_to_user_mode+0x5f/0x90 > > > [ 25.823823][ T214] ? __do_fast_syscall_32+0x7c/0xd0 > > > [ 25.824259][ T214] ? lockdep_hardirqs_on_prepare+0x242/0x400 > > > [ 25.824767][ T214] ? syscall_exit_to_user_mode+0x5f/0x90 > > > [ 25.825254][ T214] ? __do_fast_syscall_32+0x7c/0xd0 > > > [ 25.825696][ T214] ? __do_fast_syscall_32+0x7c/0xd0 > > > [ 25.826155][ T214] ? syscall_exit_to_user_mode+0x5f/0x90 > > > [ 25.826627][ T214] ? __do_fast_syscall_32+0x7c/0xd0 > > > [ 25.827056][ T214] ? __do_fast_syscall_32+0x7c/0xd0 > > > [ 25.827486][ T214] ? __do_fast_syscall_32+0x7c/0xd0 > > > [ 25.827929][ T214] ? irqentry_exit_to_user_mode+0x23/0x30 > > > [ 25.828423][ T214] ? irqentry_exit+0x7f/0xc0 > > > [ 25.828812][ T214] do_fast_syscall_32+0x32/0x70 > > > [ 25.829223][ T214] do_SYSENTER_32+0x15/0x20 > > > [ 25.829589][ T214] entry_SYSENTER_32+0xa2/0xfb > > > [ 25.830003][ T214] EIP: 0xb7f8c549 > > > [ 25.830330][ T214] Code: 03 74 c0 01 10 05 03 74 b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d 76 00 58 b8 77 00 00 00 cd 80 90 8d 76 > > > [ 25.831929][ T214] EAX: ffffffda EBX: 00000006 ECX: 006142a1 EDX: 002a8000 > > > [ 25.832522][ T214] ESI: 00000000 EDI: 00000001 EBP: 00614024 ESP: bff3c4a0 > > > [ 25.833123][ T214] DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 007b EFLAGS: 00200246 > > > [ 25.833738][ T214] Modules linked in: > > > [ 25.834062][ T214] ---[ end trace 0000000000000000 ]--- > > > [ 25.834522][ T214] EIP: __dump_page.cold+0x282/0x369 > > > [ 25.834960][ T214] Code: ff ff 83 05 e8 5d bb c5 01 ba 4c c4 2f c4 89 f8 83 15 ec 5d bb c5 00 e8 f2 92 ed fd 83 05 f8 5d bb c5 01 83 15 fc 5d bb c5 00 <0f> 0b 83 05 00 5e bb c5 01 b8 ac 85 a3 c4 83 15 04 5e bb c5 00 e8 > > > [ 25.836574][ T214] EAX: 00000000 EBX: e764d530 ECX: 00000003 EDX: 4108888f > > > [ 25.837183][ T214] ESI: e764d4e0 EDI: e764d4e0 EBP: ed89db3c ESP: ed89db00 > > > [ 25.837772][ T214] DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068 EFLAGS: 00210046 > > > [ 25.838414][ T214] CR0: 80050033 CR2: 00616abc CR3: 2d878000 CR4: 000406d0 > > > [ 25.839011][ T214] DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000 > > > [ 25.839597][ T214] DR6: fffe0ff0 DR7: 00000400 > > > [ 25.839995][ T214] Kernel panic - not syncing: Fatal exception > > > [ 25.840554][ T214] Kernel Offset: disabled > > > > -- Thanks, Hyeonggon
