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Rasmus Villemoes authored
If the kmalloc() fails, we try to undo the gen_pool allocation we've just done. Unfortunately, start has already been modified to subtract the GENPOOL_OFFSET bias, so we're freeing something that very likely doesn't exist in the gen_pool, meaning we hit the kernel BUG at lib/genalloc.c:399! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM ... [<803fd0e8>] (gen_pool_free) from [<80426bc8>] (cpm_muram_alloc_common+0xb0/0xc8) [<80426bc8>] (cpm_muram_alloc_common) from [<80426c28>] (cpm_muram_alloc+0x48/0x80) [<80426c28>] (cpm_muram_alloc) from [<80428214>] (ucc_slow_init+0x110/0x4f0) [<80428214>] (ucc_slow_init) from [<8044a718>] (qe_uart_request_port+0x3c/0x1d8) (this was tested by just injecting a random failure by adding "|| (get_random_int()&7) == 0" to the "if (!entry)" condition). Refactor the code so we do the kmalloc() first, meaning that's the thing that needs undoing in case gen_pool_alloc_algo() then fails. This allows a later cleanup to move the locking from the callers into the _common function, keeping the kmalloc() out of the critical region and then, hopefully (if all the muram_alloc callers allow) change it to a GFP_KERNEL allocation. Reviewed-by:
Timur Tabi <timur@kernel.org> Signed-off-by:
Rasmus Villemoes <linux@rasmusvillemoes.dk> Signed-off-by:
Li Yang <leoyang.li@nxp.com>
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