| Message ID | 20240709115841.4098393-1-linmiaohe@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/hugetlb: fix kernel NULL pointer dereference when migrating hugetlb folio | expand |
On 2024/7/9 19:58, Miaohe Lin wrote: > A kernel crash was observed when migrating hugetlb folio: > > BUG: kernel NULL pointer dereference, address: 0000000000000008 > PGD 0 P4D 0 > Oops: Oops: 0002 [#1] PREEMPT SMP NOPTI > CPU: 0 PID: 3435 Comm: bash Not tainted 6.10.0-rc6-00450-g8578ca01f21f #66 > RIP: 0010:__folio_undo_large_rmappable+0x70/0xb0 > RSP: 0018:ffffb165c98a7b38 EFLAGS: 00000097 > RAX: fffffbbc44528090 RBX: 0000000000000000 RCX: 0000000000000000 > RDX: ffffa30e000a2800 RSI: 0000000000000246 RDI: ffffa3153ffffcc0 > RBP: fffffbbc44528000 R08: 0000000000002371 R09: ffffffffbe4e5868 > R10: 0000000000000001 R11: 0000000000000001 R12: ffffa3153ffffcc0 > R13: fffffbbc44468000 R14: 0000000000000001 R15: 0000000000000001 > FS: 00007f5b3a716740(0000) GS:ffffa3151fc00000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: 0000000000000008 CR3: 000000010959a000 CR4: 00000000000006f0 > Call Trace: > <TASK> > __folio_migrate_mapping+0x59e/0x950 > __migrate_folio.constprop.0+0x5f/0x120 > move_to_new_folio+0xfd/0x250 > migrate_pages+0x383/0xd70 > soft_offline_page+0x2ab/0x7f0 > soft_offline_page_store+0x52/0x90 > kernfs_fop_write_iter+0x12c/0x1d0 > vfs_write+0x380/0x540 > ksys_write+0x64/0xe0 > do_syscall_64+0xb9/0x1d0 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7f5b3a514887 > RSP: 002b:00007ffe138fce68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 > RAX: ffffffffffffffda RBX: 000000000000000c RCX: 00007f5b3a514887 > RDX: 000000000000000c RSI: 0000556ab809ee10 RDI: 0000000000000001 > RBP: 0000556ab809ee10 R08: 00007f5b3a5d1460 R09: 000000007fffffff > R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000c > R13: 00007f5b3a61b780 R14: 00007f5b3a617600 R15: 00007f5b3a616a00 > > It's because hugetlb folio is passed to __folio_undo_large_rmappable() > unexpectedly. large_rmappable flag is imperceptibly set to hugetlb folio > since commit f6a8dd98a2ce ("hugetlb: convert alloc_buddy_hugetlb_folio to > use a folio"). Then commit be9581ea8c05 ("mm: fix crashes from deferred > split racing folio migration") makes folio_migrate_mapping() call > folio_undo_large_rmappable() triggering the bug. Fix this issue by > clearing large_rmappable flag for hugetlb folios. They don't need that > flag set anyway. > > Fixes: f6a8dd98a2ce ("hugetlb: convert alloc_buddy_hugetlb_folio to use a folio") > Fixes: be9581ea8c05 ("mm: fix crashes from deferred split racing folio migration") > Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> > Cc: <stable@vger.kernel.org> Sorry for make noise. This is not newest version. Will resend soon. Thanks. .
diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 6282dd9e37e3..4e288757da19 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2173,6 +2173,8 @@ static struct folio *alloc_buddy_hugetlb_folio(struct hstate *h, nid = numa_mem_id(); retry: folio = __folio_alloc(gfp_mask, order, nid, nmask); + /* Ensure hugetlb folio won't have large_rmappable flag set. */ + folio_clear_large_rmappable(folio); if (folio && !folio_ref_freeze(folio, 1)) { folio_put(folio);
A kernel crash was observed when migrating hugetlb folio: BUG: kernel NULL pointer dereference, address: 0000000000000008 PGD 0 P4D 0 Oops: Oops: 0002 [#1] PREEMPT SMP NOPTI CPU: 0 PID: 3435 Comm: bash Not tainted 6.10.0-rc6-00450-g8578ca01f21f #66 RIP: 0010:__folio_undo_large_rmappable+0x70/0xb0 RSP: 0018:ffffb165c98a7b38 EFLAGS: 00000097 RAX: fffffbbc44528090 RBX: 0000000000000000 RCX: 0000000000000000 RDX: ffffa30e000a2800 RSI: 0000000000000246 RDI: ffffa3153ffffcc0 RBP: fffffbbc44528000 R08: 0000000000002371 R09: ffffffffbe4e5868 R10: 0000000000000001 R11: 0000000000000001 R12: ffffa3153ffffcc0 R13: fffffbbc44468000 R14: 0000000000000001 R15: 0000000000000001 FS: 00007f5b3a716740(0000) GS:ffffa3151fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 000000010959a000 CR4: 00000000000006f0 Call Trace: <TASK> __folio_migrate_mapping+0x59e/0x950 __migrate_folio.constprop.0+0x5f/0x120 move_to_new_folio+0xfd/0x250 migrate_pages+0x383/0xd70 soft_offline_page+0x2ab/0x7f0 soft_offline_page_store+0x52/0x90 kernfs_fop_write_iter+0x12c/0x1d0 vfs_write+0x380/0x540 ksys_write+0x64/0xe0 do_syscall_64+0xb9/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f5b3a514887 RSP: 002b:00007ffe138fce68 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000000000c RCX: 00007f5b3a514887 RDX: 000000000000000c RSI: 0000556ab809ee10 RDI: 0000000000000001 RBP: 0000556ab809ee10 R08: 00007f5b3a5d1460 R09: 000000007fffffff R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000c R13: 00007f5b3a61b780 R14: 00007f5b3a617600 R15: 00007f5b3a616a00 It's because hugetlb folio is passed to __folio_undo_large_rmappable() unexpectedly. large_rmappable flag is imperceptibly set to hugetlb folio since commit f6a8dd98a2ce ("hugetlb: convert alloc_buddy_hugetlb_folio to use a folio"). Then commit be9581ea8c05 ("mm: fix crashes from deferred split racing folio migration") makes folio_migrate_mapping() call folio_undo_large_rmappable() triggering the bug. Fix this issue by clearing large_rmappable flag for hugetlb folios. They don't need that flag set anyway. Fixes: f6a8dd98a2ce ("hugetlb: convert alloc_buddy_hugetlb_folio to use a folio") Fixes: be9581ea8c05 ("mm: fix crashes from deferred split racing folio migration") Signed-off-by: Miaohe Lin <linmiaohe@huawei.com> Cc: <stable@vger.kernel.org> --- mm/hugetlb.c | 2 ++ 1 file changed, 2 insertions(+)