b84a8aba80
irq_find_at_or_after() dereferences the interrupt descriptor which is
returned by mt_find() while neither holding sparse_irq_lock nor RCU read
lock, which means the descriptor can be freed between mt_find() and the
dereference:
CPU0 CPU1
desc = mt_find()
delayed_free_desc(desc)
irq_desc_get_irq(desc)
The use-after-free is reported by KASAN:
Call trace:
irq_get_next_irq+0x58/0x84
show_stat+0x638/0x824
seq_read_iter+0x158/0x4ec
proc_reg_read_iter+0x94/0x12c
vfs_read+0x1e0/0x2c8
Freed by task 4471:
slab_free_freelist_hook+0x174/0x1e0
__kmem_cache_free+0xa4/0x1dc
kfree+0x64/0x128
irq_kobj_release+0x28/0x3c
kobject_put+0xcc/0x1e0
delayed_free_desc+0x14/0x2c
rcu_do_batch+0x214/0x720
Guard the access with a RCU read lock section.
Fixes:
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.. | ||
affinity.c | ||
autoprobe.c | ||
chip.c | ||
cpuhotplug.c | ||
debug.h | ||
debugfs.c | ||
devres.c | ||
dummychip.c | ||
generic-chip.c | ||
handle.c | ||
internals.h | ||
ipi-mux.c | ||
ipi.c | ||
irq_sim.c | ||
irqdesc.c | ||
irqdomain.c | ||
Kconfig | ||
Makefile | ||
manage.c | ||
matrix.c | ||
migration.c | ||
msi.c | ||
pm.c | ||
proc.c | ||
resend.c | ||
settings.h | ||
spurious.c | ||
timings.c |