在 2025/01/24 9:30, Yu Kuai 写道:

Hi,

在 2025/01/23 5:58, Harshit Mogalapalli 写道:

...

Hi all,

We started seeing panic during boot cycle on 6.12 upstream kernel.

Data points:

• This is reproducible on 6.12.9
• Also reproducible on 6.13 from yesterday.
• Not reproducible on 6.11

So I looked at commits between 6.11-> 6.12 , and narrowed it down to a patch series which made changed to md-bitmap.c

https://lore.kernel.org/all/20240826074452.1490072-1-yukuai1@huaweicloud.com...

After narrowing down further: it is narrowed down to this commit

ec6bb299c7c3 md/md-bitmap: add 'sync_size' into struct md_bitmap_stats

#regzbot introduced: ec6bb299c7c3

Also, the panic points to the middle line below:

sb = kmap_local_page(bitmap->storage.sb_page); *    stats->sync_size = le64_to_cpu(sb->sync_size);      kunmap_local(sb);

Call trace is as follows:

[   21.427462] Oops: general protection fault, probably for non-canonical address 0x8730d3f80000028: 0000 [#1] PREEMPT SMP NOPTI [   21.440104] CPU: 56 UID: 0 PID: 1531 Comm: mdadm Not tainted 6.13.0-master.20250121.ol8.x86_64 #1 [   21.450019] Hardware name: Oracle Corporation ORACLE SERVER X9-2L/ASM,MTHRBD,2U, BIOS 62110100 07/15/2024 [   21.460710] RIP: 0010:bitmap_get_stats+0x2b/0xa0 [   21.465872] Code: 0f 1e fa 0f 1f 44 00 00 48 89 f2 48 85 ff 74 7d 48 8b 4f 50 48 2b 0d dc 9f e5 00 48 8b 35 e5 9f e5 00 48 c1 f9 06 48 c1 e1 0c <48> 8b 4c 31 28 48 89 4a 20 48 8b 4f 18 48 89 4a 10 48 8b 4f 10 48 [   21.486849] RSP: 0018:ff3e5f658fc3fb18 EFLAGS: 00010206 [   21.492690] RAX: ffffffff8d17d660 RBX: ff27d0600af69690 RCX: 094b3d0000000000 [   21.500663] RDX: ff3e5f658fc3fb28 RSI: ff27d03f80000000 RDI: ff27d06008cd9c00 [   21.507233] mlx5_core 0000:b1:00.0: Rate limit: 127 rates are supported, range: 0Mbps to 97656Mbps [   21.508629] RBP: ff27d0604a737418 R08: 0000000000000000 R09: 0000000000000000 [   21.508631] R10: 0000000000000000 R11: 0000000000000000 R12: 00000000012c2000 [   21.508631] R13: ff27d0604a737018 R14: ff27d0604a737000 R15: ff27d0604a737018 [   21.508632] FS:  00007f61a01c98c0(0000) GS:ff27d07f7f600000(0000) knlGS:0000000000000000 [   21.508634] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [   21.508635] CR2: 000056503c28f458 CR3: 00000020c000c004 CR4: 0000000000771ef0 [   21.518772] mlx5_core 0000:b1:00.0: E-Switch: Total vports 27, per vport: max uc(128) max mc(2048) [   21.526600] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [   21.526601] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [   21.526602] PKRU: 55555554 [   21.526603] Call Trace: [   21.526604]  <TASK> [   21.535111] mlx5_core 0000:b1:00.0: Flow counters bulk query buffer size increased, bulk_query_len(8) [   21.542533]  ? show_trace_log_lvl+0x1b0/0x300 [   21.542537]  ? show_trace_log_lvl+0x1b0/0x300 [   21.556126] mlx5_core 0000:b1:00.0: mlx5_pcie_event:301:(pid 529): PCIe slot advertised sufficient power (27W). [   21.557983]  ? md_seq_show+0x2d2/0x5b0 [   21.557988]  ? __die_body.cold+0x8/0x12 [   21.641128]  ? die_addr+0x3c/0x60 [   21.645080]  ? exc_general_protection+0x17d/0x400 [   21.650574]  ? asm_exc_general_protection+0x26/0x30 [   21.656267]  ? __pfx_bitmap_get_stats+0x10/0x10 [   21.661568]  ? bitmap_get_stats+0x2b/0xa0 [   21.666277]  md_seq_show+0x2d2/0x5b0 [   21.670507]  seq_read_iter+0x2b9/0x470 [   21.674924]  seq_read+0x12f/0x180 [   21.678853]  proc_reg_read+0x57/0xb0 [   21.683074]  vfs_read+0xf6/0x380 [   21.686902]  ? __seccomp_filter+0x30b/0x520 [   21.691786]  ksys_read+0x6c/0xf0 [   21.695607]  do_syscall_64+0x82/0x170 [   21.699909]  ? arch_exit_to_user_mode_prepare.isra.0+0x1e/0xd0 [   21.706637]  ? syscall_exit_to_user_mode+0x37/0x1a0 [   21.712295]  ? __memcg_slab_free_hook+0xf7/0x160 [   21.717660]  ? __x64_sys_close+0x3c/0x80 [   21.722248]  ? kmem_cache_free+0x400/0x460 [   21.727028]  ? syscall_exit_to_user_mode_prepare+0x174/0x1b0 [   21.733553]  ? arch_exit_to_user_mode_prepare.isra.0+0x1e/0xd0 [   21.740270]  ? syscall_exit_to_user_mode+0x37/0x1a0 [   21.745913]  ? do_syscall_64+0x8e/0x170 [   21.750388]  ? do_syscall_64+0x8e/0x170 [   21.754857]  ? clear_bhb_loop+0x45/0xa0 [   21.759318]  ? clear_bhb_loop+0x45/0xa0 [   21.763772]  ? clear_bhb_loop+0x45/0xa0 [   21.768218]  entry_SYSCALL_64_after_hwframe+0x76/0x7e [   21.774014] RIP: 0033:0x7f619f862585 [   21.778170] Code: fe ff ff 50 48 8d 3d 52 a8 06 00 e8 e5 08 02 00 0f 1f 44 00 00 f3 0f 1e fa 48 8d 05 d5 71 2a 00 8b 00 85 c0 75 0f 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 53 c3 66 90 41 54 49 89 d4 55 48 89 f5 53 89 [   21.799471] RSP: 002b:00007ffe50c2d3c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000 [   21.808099] RAX: ffffffffffffffda RBX: 000056503c2802a0 RCX: 00007f619f862585 [   21.816240] RDX: 0000000000000400 RSI: 000056503c28d000 RDI: 0000000000000004 [   21.824382] RBP: 0000000000000d68 R08: 0000000000000008 R09: 0000000000000001 [   21.832518] R10: 0000000000000000 R11: 0000000000000246 R12: 00007f619fb00860 [   21.840654] R13: 00007f619fb013a0 R14: 000056503c280a50 R15: 000056503c281480 [   21.848789]  </TASK> [   21.851389] Modules linked in: raid1 mgag200 drm_client_lib drm_shmem_helper drm_kms_helper sd_mod sg raid0 mlx5_core(+) ahci libahci drm crct10dif_pclmul ghash_clmulni_intel mlxfw sha512_ssse3 igb nvme sha256_ssse3 libata tls sha1_ssse3 megaraid_sas nvme_core pci_hyperv_intf psample dca nvme_auth i2c_algo_bit nfit(+) libnvdimm aesni_intel gf128mul crypto_simd cryptd [   21.888253] ---[ end trace 0000000000000000 ]--- [   22.452319] RIP: 0010:bitmap_get_stats+0x2b/0xa0 [   22.457699] Code: 0f 1e fa 0f 1f 44 00 00 48 89 f2 48 85 ff 74 7d 48 8b 4f 50 48 2b 0d dc 9f e5 00 48 8b 35 e5 9f e5 00 48 c1 f9 06 48 c1 e1 0c <48> 8b 4c 31 28 48 89 4a 20 48 8b 4f 18 48 89 4a 10 48 8b 4f 10 48 [   22.479037] RSP: 0018:ff3e5f658fc3fb18 EFLAGS: 00010206 [   22.485067] RAX: ffffffff8d17d660 RBX: ff27d0600af69690 RCX: 094b3d0000000000 [   22.493217] RDX: ff3e5f658fc3fb28 RSI: ff27d03f80000000 RDI: ff27d06008cd9c00 [   22.501372] RBP: ff27d0604a737418 R08: 0000000000000000 R09: 0000000000000000 [   22.509527] R10: 0000000000000000 R11: 0000000000000000 R12: 00000000012c2000 [   22.517686] R13: ff27d0604a737018 R14: ff27d0604a737000 R15: ff27d0604a737018 [   22.525845] FS:  00007f61a01c98c0(0000) GS:ff27d07f7f600000(0000) knlGS:0000000000000000 [   22.535089] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [   22.541701] CR2: 000056503c28f458 CR3: 00000020c000c004 CR4: 0000000000771ef0 [   22.549866] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [   22.558040] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [   22.566202] PKRU: 55555554 [   22.569425] Kernel panic - not syncing: Fatal exception [   22.576477] Kernel Offset: 0xb600000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff) [   22.654941] Rebooting in 60 seconds..

I would be happy to try any patches.

Can you try the following patch on latest kernel?

Thanks for the report! Kuai

Please use this patch, I found that last patch has problem while testing.

Thanks,

diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c index 63879582d1c3..e01c2d0479e3 100644 --- a/drivers/md/md-bitmap.c +++ b/drivers/md/md-bitmap.c @@ -2340,7 +2340,10 @@ static int bitmap_get_stats(void *data, struct md_bitmap_stats *stats)

if (!bitmap) return -ENOENT; - + if (bitmap->mddev->bitmap_info.external) + return -ENOENT; + if (!bitmap->storage.sb_page) /* no superblock */ + return -EINVAL; sb = kmap_local_page(bitmap->storage.sb_page); stats->sync_size = le64_to_cpu(sb->sync_size); kunmap_local(sb); diff --git a/drivers/md/md.c b/drivers/md/md.c index 94166b2e9512..c9de57701e43 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -8470,6 +8470,10 @@ static int md_seq_show(struct seq_file *seq, void *v) return 0;

spin_unlock(&all_mddevs_lock); + + /* prevent bitmap to be freed after checking */ + mutex_lock(&mddev->bitmap_info.mutex); + spin_lock(&mddev->lock); if (mddev->pers || mddev->raid_disks || !list_empty(&mddev->disks)) { seq_printf(seq, "%s : ", mdname(mddev)); @@ -8545,6 +8549,7 @@ static int md_seq_show(struct seq_file *seq, void *v) seq_printf(seq, "\n"); } spin_unlock(&mddev->lock); + mutex_unlock(&mddev->bitmap_info.mutex); spin_lock(&all_mddevs_lock);

if (mddev == list_last_entry(&all_mddevs, struct mddev, all_mddevs))

diff --git a/drivers/md/md.c b/drivers/md/md.c index 94166b2e9512..b07e9c595a7c 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -8429,12 +8429,14 @@ static void md_bitmap_status(struct seq_file *seq, struct mddev *mddev)         unsigned long chunk_kb;         int err;

+       /* prevent bitmap to be freed after checking */ +       mutex_lock(&mddev->bitmap_info.mutex);         if (!md_bitmap_enabled(mddev)) -               return; +               goto out;

err = mddev->bitmap_ops->get_stats(mddev->bitmap, &stats);         if (err) -               return; +               goto out;

chunk_kb = mddev->bitmap_info.chunksize >> 10;         used_pages = stats.pages - stats.missing_pages; @@ -8450,6 +8452,9 @@ static void md_bitmap_status(struct seq_file *seq, struct mddev *mddev)         }

seq_putc(seq, '\n');

+out: +       mutex_unlock(&mddev->bitmap_info.mutex);  }

static int md_seq_show(struct seq_file *seq, void *v)

...

Thanks, Harshit

.