btrfs: reclaim compression cache in shrinker-sized batches - #10

commit 6d827ad upstream.
When meson_allocate_chanlist() fails after a partial allocation, it already
unwinds the allocated chanlist state through its local error path.
meson_crypto_probe() then jump to error_flow and calls
meson_free_chanlist() again, causing the same per-flow resources to be torn
down twice. In the reproduced failure path, the second teardown
re-entered crypto_engine_exit() on an already destroyed worker and KASAN
reported a slab-use-after-free in kthread_destroy_worker().
Prevent double-free by handling partial allocation failures locally within
meson_allocate_chanlist() and skipping the outer cleanup path.
The bug was first flagged by an experimental analysis tool we are
developing for kernel memory-management bugs while analyzing
v6.13-rc1. The tool is still under development and is not yet publicly
available.
The bug was reproduced in a QEMU x86_64 guest booted with KASAN on v7.1,
using the reproducer under tools/testing/meson_crypto_probe. The reproducer
forces the second dma_alloc_attrs() call in the gxl-crypto probe path to
return NULL, making meson_allocate_chanlist() fail after partial
initialization. On the unpatched kernel this reliably triggered a
slab-use-after-free. With this fix applied, the same reproducer no longer
emits any KASAN report and the probe fails cleanly with -ENOMEM.
 ==================================================================
 BUG: KASAN: slab-use-after-free in kthread_destroy_worker+0xb2/0xd0
 Read of size 8 at addr ff1100010c057a68 by task insmod/265
 CPU: 1 UID: 0 PID: 265 Comm: insmod Tainted: G O 7.1.0-rc2-00376-g810af9adc907-dirty CachyOS#10 PREEMPT(lazy)
 Tainted: [O]=OOT_MODULE
 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014
 Call Trace:
 <TASK>
 dump_stack_lvl+0x68/0xa0
 print_report+0xcb/0x5e0
 ? __virt_addr_valid+0x21d/0x3f0
 ? kthread_destroy_worker+0xb2/0xd0
 ? kthread_destroy_worker+0xb2/0xd0
 kasan_report+0xca/0x100
 ? kthread_destroy_worker+0xb2/0xd0
 kthread_destroy_worker+0xb2/0xd0
 meson_crypto_probe+0x4d0/0xc10 [amlogic_gxl_crypto]
 platform_probe+0x99/0x140
 really_probe+0x1c6/0x6a0
 ? __pfx___device_attach_driver+0x10/0x10
 __driver_probe_device+0x248/0x310
 ? acpi_driver_match_device+0xb0/0x100
 driver_probe_device+0x48/0x210
 ? __pfx___device_attach_driver+0x10/0x10
 __device_attach_driver+0x160/0x320
 bus_for_each_drv+0x104/0x190
 ? __pfx_bus_for_each_drv+0x10/0x10
 ? _raw_spin_unlock_irqrestore+0x2c/0x50
 __device_attach+0x19d/0x3b0
 ? __pfx___device_attach+0x10/0x10
 ? do_raw_spin_unlock+0x53/0x220
 device_initial_probe+0x78/0xa0
 bus_probe_device+0x5b/0x130
 device_add+0xcfd/0x1430
 ? __pfx_device_add+0x10/0x10
 ? insert_resource+0x34/0x50
 ? lock_release+0xc9/0x290
 platform_device_add+0x24e/0x590
 ? __pfx_meson_crypto_probe_repro_init+0x10/0x10 [meson_crypto_probe_repro]
 meson_crypto_probe_repro_init+0x330/0xff0 [meson_crypto_probe_repro]
 do_one_initcall+0xc0/0x450
 ? __pfx_do_one_initcall+0x10/0x10
 ? _raw_spin_unlock_irqrestore+0x2c/0x50
 ? __create_object+0x59/0x80
 ? kasan_unpoison+0x27/0x60
 do_init_module+0x27b/0x7d0
 ? __pfx_do_init_module+0x10/0x10
 ? kasan_quarantine_put+0x84/0x1d0
 ? kfree+0x32c/0x510
 ? load_module+0x561e/0x5ff0
 load_module+0x54fe/0x5ff0
 ? __pfx_load_module+0x10/0x10
 ? security_file_permission+0x20/0x40
 ? kernel_read_file+0x23d/0x6e0
 ? mmap_region+0x235/0x4a0
 ? __pfx_kernel_read_file+0x10/0x10
 ? __file_has_perm+0x2c0/0x3e0
 init_module_from_file+0x158/0x180
 ? __pfx_init_module_from_file+0x10/0x10
 ? __lock_acquire+0x45a/0x1ba0
 ? idempotent_init_module+0x315/0x610
 ? lock_release+0xc9/0x290
 ? lockdep_init_map_type+0x4b/0x220
 ? do_raw_spin_unlock+0x53/0x220
 idempotent_init_module+0x330/0x610
 ? __pfx_idempotent_init_module+0x10/0x10
 ? __pfx_cred_has_capability.isra.0+0x10/0x10
 ? ksys_mmap_pgoff+0x385/0x520
 __x64_sys_finit_module+0xbe/0x120
 do_syscall_64+0x115/0x690
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
 RIP: 0033:0x7f7d6d31690d
 Code: 5b 41 5c c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d f3 b4 0f 00 f7 d8 >
 RSP: 002b:00007fffc027ac68 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
 RAX: ffffffffffffffda RBX: 000055f7b81967c0 RCX: 00007f7d6d31690d
 RDX: 0000000000000000 RSI: 000055f79a0d6cd2 RDI: 0000000000000003
 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000000000003 R11: 0000000000000246 R12: 000055f79a0d6cd2
 R13: 000055f7b8196790 R14: 000055f79a0d5888 R15: 000055f7b81968e0
 </TASK>
Fixes: 48fe583 ("crypto: amlogic - Add crypto accelerator for amlogic GXL")
Cc: stable@vger.kernel.org
Signed-off-by: Zilin Guan <zilin@seu.edu.cn>
Signed-off-by: Dawei Feng <dawei.feng@seu.edu.cn>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>