mm: vmalloc: bail out early in find_vmap_area() if vmap is not init

mainline inclusion
from mainline-v6.9-rc3
commit 4ed91fa9177b236b73a271f11a333a98f076eb63
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I9S4Z4
CVE: NA

-------------------------------------------------

During the boot the s390 system triggers "spinlock bad magic" messages
if the spinlock debugging is enabled:

[    0.465445] BUG: spinlock bad magic on CPU#0, swapper/0
[    0.465490]  lock: single+0x1860/0x1958, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
[    0.466067] CPU: 0 PID: 0 Comm: swapper Not tainted 6.8.0-12955-g8e938e398669 #1
[    0.466188] Hardware name: QEMU 8561 QEMU (KVM/Linux)
[    0.466270] Call Trace:
[    0.466470]  [<00000000011f26c8>] dump_stack_lvl+0x98/0xd8
[    0.466516]  [<00000000001dcc6a>] do_raw_spin_lock+0x8a/0x108
[    0.466545]  [<000000000042146c>] find_vmap_area+0x6c/0x108
[    0.466572]  [<000000000042175a>] find_vm_area+0x22/0x40
[    0.466597]  [<000000000012f152>] __set_memory+0x132/0x150
[    0.466624]  [<0000000001cc0398>] vmem_map_init+0x40/0x118
[    0.466651]  [<0000000001cc0092>] paging_init+0x22/0x68
[    0.466677]  [<0000000001cbbed2>] setup_arch+0x52a/0x708
[    0.466702]  [<0000000001cb6140>] start_kernel+0x80/0x5c8
[    0.466727]  [<0000000000100036>] startup_continue+0x36/0x40

it happens because such system tries to access some vmap areas
whereas the vmalloc initialization is not even yet done:

[    0.465490] lock: single+0x1860/0x1958, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
[    0.466067] CPU: 0 PID: 0 Comm: swapper Not tainted 6.8.0-12955-g8e938e398669 #1
[    0.466188] Hardware name: QEMU 8561 QEMU (KVM/Linux)
[    0.466270] Call Trace:
[    0.466470] dump_stack_lvl (lib/dump_stack.c:117)
[    0.466516] do_raw_spin_lock (kernel/locking/spinlock_debug.c:87 kernel/locking/spinlock_debug.c:115)
[    0.466545] find_vmap_area (mm/vmalloc.c:1059 mm/vmalloc.c:2364)
[    0.466572] find_vm_area (mm/vmalloc.c:3150)
[    0.466597] __set_memory (arch/s390/mm/pageattr.c:360 arch/s390/mm/pageattr.c:393)
[    0.466624] vmem_map_init (./arch/s390/include/asm/set_memory.h:55 arch/s390/mm/vmem.c:660)
[    0.466651] paging_init (arch/s390/mm/init.c:97)
[    0.466677] setup_arch (arch/s390/kernel/setup.c:972)
[    0.466702] start_kernel (init/main.c:899)
[    0.466727] startup_continue (arch/s390/kernel/head64.S:35)
[    0.466811] INFO: lockdep is turned off.
...
[    0.718250] vmalloc init - busy lock init 0000000002871860
[    0.718328] vmalloc init - busy lock init 00000000028731b8

Some background. It worked before because the lock that is in question
was statically defined and initialized. As of now, the locks and data
structures are initialized in the vmalloc_init() function.

To address that issue add the check whether the "vmap_initialized"
variable is set, if not find_vmap_area() bails out on entry returning NULL.

Link: https://lkml.kernel.org/r/20240323141544.4150-1-urezki@gmail.com


Fixes: 72210662c5a2 ("mm: vmalloc: offload free_vmap_area_lock lock")
Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleksiy Avramchenko <oleksiy.avramchenko@sony.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
(cherry picked from commit 4ed91fa9177b236b73a271f11a333a98f076eb63)
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>