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author | Rasmus Villemoes <linux@rasmusvillemoes.dk> | 2019-11-28 15:55:44 +0100 |
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committer | Li Yang <leoyang.li@nxp.com> | 2019-12-09 13:54:36 -0600 |
commit | ec2058ac8f507865f7a7c353473bf0f4ebce5fc0 (patch) | |
tree | 621c48626ef3389a12bd2601120a7105c47f9eff /include/soc | |
parent | b6231ea2b3c68101da186f0d274635a620dbf7a4 (diff) | |
download | linux-ec2058ac8f507865f7a7c353473bf0f4ebce5fc0.tar.bz2 |
soc: fsl: qe: refactor cpm_muram_alloc_common to prevent BUG on error path
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>
Diffstat (limited to 'include/soc')
0 files changed, 0 insertions, 0 deletions