APPLIED(cmnt): [PATCH] [SRU] [B/master][C/master] Fix reserve_memblock_reserved_regions() upon boot

[Khaled Elmously]

Added "UBUNTU: SAUCE: " also


On 2018-10-10 16:30:33 , Paolo Pisati wrote:
> Impact:
> 
> During boot on a dragonboard410c using a recent Bionic or Cosmic kernel:
> 
> ...
> [ 0.049776] WARNING: CPU: 0 PID: 1 at arch/arm64/kernel/setup.c:271 reserve_memblock_reserved_regions+0xe0/0x148
> [ 0.049783] Modules linked in:
> [ 0.049797] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.18.0-8-snapdragon #9
> [ 0.049803] Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT)
> [ 0.049813] pstate: 80400005 (Nzcv daif +PAN -UAO)
> [ 0.049821] pc : reserve_memblock_reserved_regions+0xe0/0x148
> [ 0.049829] lr : reserve_memblock_reserved_regions+0xd8/0x148
> [ 0.049836] sp : ffff000008033d40
> [ 0.049841] x29: ffff000008033d40 x28: 0000000000000000
> [ 0.049852] x27: ffff000009410584 x26: ffff000009577018
> [ 0.049863] x25: 0000000000000000 x24: 0000000000488020
> [ 0.049874] x23: 00000000bfffffff x22: ffff0000090e8928
> [ 0.049885] x21: ffff000008ffb578 x20: ffff000009a48708
> [ 0.049896] x19: ffff80003a409280 x18: 0000000000000000
> [ 0.049906] x17: 0000000000000000 x16: 0000000000000000
> [ 0.049917] x15: ffffffffffffffff x14: ffff000009a48708
> [ 0.049927] x13: 0000000000000000 x12: 0000000000000028
> [ 0.049938] x11: 0101010101010101 x10: 7f7f7f7f7f7f7f7f
> [ 0.049949] x9 : 0000000000000000 x8 : ffff80003a409300
> [ 0.049959] x7 : 0000000000000000 x6 : 000000000000003f
> [ 0.049969] x5 : 0000000000000040 x4 : ffff80003d9ffc70
> [ 0.049980] x3 : 00000000bd9fffff x2 : ffff000009c241b0
> [ 0.049990] x1 : 0000000000000000 x0 : 0000000000000000
> [ 0.050001] Call trace:
> [ 0.050010] reserve_memblock_reserved_regions+0xe0/0x148
> [ 0.050021] do_one_initcall+0x54/0x1e0
> [ 0.050031] kernel_init_freeable+0x254/0x2f8
> [ 0.050043] kernel_init+0x18/0x110
> [ 0.050052] ret_from_fork+0x10/0x18
> [ 0.050063] ---[ end trace dc768b294fafe4aa ]---
> ...
> 
> commit 50d7ba36b916 upstream ("arm64: export memblock_reserve()d regions via
> /proc/iomem"), backported in commit 62289841 in bionic/master, wrongly assumed
> that memblock_reserve() would not be used to reserve regions that aren't
> memory. It turns out, this is exactly what early_init_dt_reserve_memory_arch()
> will do if it finds a reservation that was also carved out of the memory node.
> 
> Fix:
> 
> Apply the attached patch and recompile
> 
> The fix was discussed here: https://www.spinics.net/lists/arm-kernel/msg675580.html
> 
> How to test:
> 
> Boot the patched kernel and check for the above WARNING in dmesg
> 
> Regression potential:
> 
> The patch didn't make it upstream yet, but the fix is very small and was tested on the lkml.
> 
> Proposing for Bionic and Cosmic.
> 
> James Morse (1):
>   arm64: Fix /proc/iomem for reserved but not memory regions
> 
>  arch/arm64/kernel/setup.c | 50 +++++++++++++++++++++++++++++------------------
>  1 file changed, 31 insertions(+), 19 deletions(-)
> 
> -- 
> 2.7.4
> 
> 
> -- 
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