CVE-2022-49265

In the Linux kernel, the following vulnerability has been resolved:

PM: domains: Fix sleep-in-atomic bug caused by genpd_debug_remove()

When a genpd with GENPD_FLAG_IRQ_SAFE gets removed, the following sleep-in-atomic bug will be seen, as genpd_debug_remove() will be called with a spinlock being held.

[ 0.029183] BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:1460 [ 0.029204] in_atomic(): 1, irqs_disabled(): 128, non_block: 0, pid: 1, name: swapper/0 [ 0.029219] preempt_count: 1, expected: 0 [ 0.029230] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.17.0-rc4+ #489 [ 0.029245] Hardware name: Thundercomm TurboX CM2290 (DT) [ 0.029256] Call trace: [ 0.029265] dump_backtrace.part.0+0xbc/0xd0 [ 0.029285] show_stack+0x3c/0xa0 [ 0.029298] dump_stack_lvl+0x7c/0xa0 [ 0.029311] dump_stack+0x18/0x34 [ 0.029323] __might_resched+0x10c/0x13c [ 0.029338] __might_sleep+0x4c/0x80 [ 0.029351] down_read+0x24/0xd0 [ 0.029363] lookup_one_len_unlocked+0x9c/0xcc [ 0.029379] lookup_positive_unlocked+0x10/0x50 [ 0.029392] debugfs_lookup+0x68/0xac [ 0.029406] genpd_remove.part.0+0x12c/0x1b4 [ 0.029419] of_genpd_remove_last+0xa8/0xd4 [ 0.029434] psci_cpuidle_domain_probe+0x174/0x53c [ 0.029449] platform_probe+0x68/0xe0 [ 0.029462] really_probe+0x190/0x430 [ 0.029473] __driver_probe_device+0x90/0x18c [ 0.029485] driver_probe_device+0x40/0xe0 [ 0.029497] __driver_attach+0xf4/0x1d0 [ 0.029508] bus_for_each_dev+0x70/0xd0 [ 0.029523] driver_attach+0x24/0x30 [ 0.029534] bus_add_driver+0x164/0x22c [ 0.029545] driver_register+0x78/0x130 [ 0.029556] __platform_driver_register+0x28/0x34 [ 0.029569] psci_idle_init_domains+0x1c/0x28 [ 0.029583] do_one_initcall+0x50/0x1b0 [ 0.029595] kernel_init_freeable+0x214/0x280 [ 0.029609] kernel_init+0x2c/0x13c [ 0.029622] ret_from_fork+0x10/0x20

It doesnt seem necessary to call genpd_debug_remove() with the lock, so move it out from locking to fix the problem.

Affected Software

References

• https://git.kernel.org/stable/c/2039163c30f886cf5638afd6993705ae9bb34a06
• https://git.kernel.org/stable/c/d1b6840d8fb9b35193d45d8fe6b4d830bfd20c3c
• https://git.kernel.org/stable/c/f6bfe8b5b2c2a5ac8bd2fc7bca3706e6c3fc26d8
• https://git.kernel.org/stable/c/fee777ea77769cc5392a34805d9d73099a223fae