On 10/27/2016 08:15 PM, kernel test robot wrote:
FYI, we noticed the following commit: https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git wb-buf-throttle commit b1fa1b67c176e41eeae2bfcc7df38117976cd92d ("block: hook up writeback throttling") in testcase: boot on test machine: qemu-system-x86_64 -enable-kvm -m 320M caused below changes: +------------------------------------------+------------+------------+ | | 70b2651552 | b1fa1b67c1 | +------------------------------------------+------------+------------+ | boot_successes | 6 | 0 | | boot_failures | 0 | 8 | | BUG:KASAN:null-ptr-deref_on_address | 0 | 8 | | calltrace:brd_init | 0 | 8 | | BUG:unable_to_handle_kernel | 0 | 8 | | Oops | 0 | 8 | | RIP:blk_register_queue | 0 | 8 | | Kernel_panic-not_syncing:Fatal_exception | 0 | 8 | +------------------------------------------+------------+------------+ [ 5.301507] Failed to find cpu0 device node [ 5.302217] Unable to detect cache hierarchy from DT for CPU 0 [ 5.307667] ================================================================== [ 5.308892] BUG: KASAN: null-ptr-deref on address 0000000000000080 [ 5.309809] Write of size 8 by task swapper/0/1 [ 5.310524] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.9.0-rc2-00008-gb1fa1b6 #1 [ 5.311774] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 5.313209] ffff88000f177b98 ffffffff8151d919 ffff88000f177c30 ffff88000b8332c0 [ 5.314683] ffff88000a5fb578 ffff88000a5fb558 ffff88000f177c20 ffffffff8121eaa6 [ 5.316133] ffff88000f177bc8 ffffffff8174da6a ffff88000a5fb578 0000000000000297 [ 5.317585] Call Trace: [ 5.318074] [<ffffffff8151d919>] dump_stack+0x83/0xba [ 5.318880] [<ffffffff8121eaa6>] kasan_report_error+0x3f6/0x4d0 [ 5.319804] [<ffffffff8174da6a>] ? dev_uevent_filter+0x2a/0x70 [ 5.320690] [<ffffffff815232ec>] ? kobject_uevent_env+0x1bc/0x570 [ 5.321637] [<ffffffff8121ec14>] kasan_report+0x34/0x40 [ 5.322453] [<ffffffff814e603b>] ? blk_register_queue+0x23b/0x250 [ 5.323363] [<ffffffff8121d541>] __asan_store8+0x61/0x70 [ 5.324212] [<ffffffff814e603b>] blk_register_queue+0x23b/0x250 [ 5.325124] [<ffffffff81500f41>] device_add_disk+0x401/0x8c0 [ 5.325999] [<ffffffff81500b40>] ? bdget_disk+0x60/0x60 [ 5.326843] [<ffffffff8150173a>] ? alloc_disk_node+0x17a/0x210 [ 5.327750] [<ffffffff8178d0d6>] ? brd_alloc+0x266/0x2a0 [ 5.328608] [<ffffffff8289d57e>] brd_init+0x106/0x22e [ 5.329407] [<ffffffff8289d478>] ? ramdisk_size+0x27/0x27 [ 5.330233] [<ffffffff8100228e>] do_one_initcall+0xae/0x230 [ 5.331103] [<ffffffff810021e0>] ? initcall_blacklisted+0x150/0x150 [ 5.332074] [<ffffffff810dfc82>] ? parse_args+0x4a2/0x6c0 [ 5.332916] [<ffffffff82844a44>] ? set_debug_rodata+0x1f/0x1f [ 5.333826] [<ffffffff828455c1>] kernel_init_freeable+0x1fa/0x2ae [ 5.334740] [<ffffffff81d48660>] ? rest_init+0xa0/0xa0 [ 5.335577] [<ffffffff81d48673>] kernel_init+0x13/0x180 [ 5.336392] [<ffffffff81d48660>] ? rest_init+0xa0/0xa0 [ 5.337214] [<ffffffff81d52af5>] ret_from_fork+0x25/0x30 [ 5.338054] ================================================================== [ 5.339219] Disabling lock debugging due to kernel taint [ 5.340080] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 [ 5.341485] IP: [<ffffffff814e603b>] blk_register_queue+0x23b/0x250 [ 5.342521] PGD 0 [ 5.342810] [ 5.343250] Oops: 0002 [#1] SMP KASAN [ 5.343877] Modules linked in: [ 5.344525] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G B 4.9.0-rc2-00008-gb1fa1b6 #1 [ 5.345863] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Debian-1.8.2-1 04/01/2014 [ 5.347247] task: ffff88000f11c000 task.stack: ffff88000f170000 [ 5.348137] RIP: 0010:[<ffffffff814e603b>] [<ffffffff814e603b>] blk_register_queue+0x23b/0x250 [ 5.349571] RSP: 0000:ffff88000f177c78 EFLAGS: 00010282 [ 5.350408] RAX: 0000000000000000 RBX: ffff88000a5fb110 RCX: 0000000000000000 [ 5.351437] RDX: 0000000000000000 RSI: 0000000000000297 RDI: 0000000000000297 [ 5.352447] RBP: ffff88000f177ca8 R08: 1ffffffff04bddfe R09: fffffbfff05359b7 [ 5.353493] R10: ffff88000f177ad7 R11: fffffbfff05359b8 R12: ffff88000b8332c0 [ 5.354526] R13: ffff88000a5fb578 R14: ffff88000a5fb558 R15: ffff88000a5fb1a0 [ 5.355565] FS: 0000000000000000(0000) GS:ffff88000f400000(0000) knlGS:0000000000000000 [ 5.356850] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 5.357744] CR2: 0000000000000080 CR3: 0000000002418000 CR4: 00000000000006b0 [ 5.358765] Stack: [ 5.359213] ffff88000b8332b0 ffff88000b833240 ffff88000b8332c0 0000000000000000 [ 5.360959] ffff88000f177d60 0000000000000000 ffff88000f177dc8 ffffffff81500f41 [ 5.363314] ffff88000b833240 ffff88000b8335c0 ffff88000b8332c0 ffff88000a5fb110 [ 5.365657] Call Trace: [ 5.366439] [<ffffffff81500f41>] device_add_disk+0x401/0x8c0 [ 5.367812] [<ffffffff81500b40>] ? bdget_disk+0x60/0x60 [ 5.369090] [<ffffffff8150173a>] ? alloc_disk_node+0x17a/0x210 [ 5.370490] [<ffffffff8178d0d6>] ? brd_alloc+0x266/0x2a0 [ 5.371869] [<ffffffff8289d57e>] brd_init+0x106/0x22e [ 5.373157] [<ffffffff8289d478>] ? ramdisk_size+0x27/0x27 [ 5.374463] [<ffffffff8100228e>] do_one_initcall+0xae/0x230 [ 5.375778] [<ffffffff810021e0>] ? initcall_blacklisted+0x150/0x150 [ 5.377213] [<ffffffff810dfc82>] ? parse_args+0x4a2/0x6c0 [ 5.396284] [<ffffffff82844a44>] ? set_debug_rodata+0x1f/0x1f [ 5.397682] [<ffffffff828455c1>] kernel_init_freeable+0x1fa/0x2ae [ 5.399213] [<ffffffff81d48660>] ? rest_init+0xa0/0xa0 [ 5.400511] [<ffffffff81d48673>] kernel_init+0x13/0x180 [ 5.401773] [<ffffffff81d48660>] ? rest_init+0xa0/0xa0 [ 5.403032] [<ffffffff81d52af5>] ret_from_fork+0x25/0x30 [ 5.404309] Code: be 42 03 00 00 48 c7 c7 20 d8 f2 81 41 bf fa ff ff ff e8 b9 72 bc ff e9 fe fe ff ff e8 af db c9 ff bf 80 00 00 00 e8 a5 74 d3 ff <48> c7 04 25 80 00 00 00 c0 68 78 04 eb 98 0f 1f 80 00 00 00 00 [ 5.415566] RIP [<ffffffff814e603b>] blk_register_queue+0x23b/0x250 [ 5.417261] RSP <ffff88000f177c78> [ 5.418228] CR2: 0000000000000080 [ 5.419143] ---[ end trace dfc7b622ec4895b5 ]--- [ 5.420284] Kernel panic - not syncing: Fatal exception
This was fixed right after the initial push, current branch is fine. -- Jens Axboe
