On Fri, Sep 03, 2021 at 11:54:23PM +0000, ci_notify@linaro.org wrote:
Successfully identified regression in *linux* in CI configuration tcwg_kernel/llvm-master-aarch64-mainline-allyesconfig. So far, this commit has regressed CI configurations:
- tcwg_kernel/llvm-master-aarch64-mainline-allyesconfig
Culprit:
<cut> commit 342f43af70dbc74f8629381998f92c060e1763a2 Author: Maurizio Lombardi <mlombard@redhat.com> Date: Thu Jul 29 15:52:50 2021 +0200
iscsi_ibft: fix crash due to KASLR physical memory remappingStarting with commit a799c2bd29d1 ("x86/setup: Consolidate early memory reservations") memory reservations have been moved earlier during the boot process, before the execution of the Kernel Address Space Layout Randomization code. setup_arch() calls the iscsi_ibft's find_ibft_region() function to find and reserve the memory dedicated to the iBFT and this function also saves a virtual pointer to the iBFT table for later use. The problem is that if KALSR is active, the physical memory gets remapped somewhere else in the virtual address space and the pointer is no longer valid, this will cause a kernel panic when the iscsi driver tries to dereference it. iBFT detected. BUG: unable to handle page fault for address: ffff888000099fd8 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] SMP PTI ..snip.. Call Trace: ? ibft_create_kobject+0x1d2/0x1d2 [iscsi_ibft] do_one_initcall+0x44/0x1d0 ? kmem_cache_alloc_trace+0x119/0x220 do_init_module+0x5c/0x270 __do_sys_init_module+0x12e/0x1b0 do_syscall_64+0x40/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae Fix this bug by saving the address of the physical location of the ibft; later the driver will use isa_bus_to_virt() to get the correct virtual address. N.B. On each reboot KASLR randomizes the virtual addresses so assuming phys_to_virt before KASLR does its deed is incorrect. Simplify the code by renaming find_ibft_region() to reserve_ibft_region() and remove all the wrappers. Signed-off-by: Maurizio Lombardi mlombard@redhat.com Reviewed-by: Mike Rapoport rppt@linux.ibm.com Signed-off-by: Konrad Rzeszutek Wilk konrad@kernel.org
</cut>
Results regressed to (for first_bad == 342f43af70dbc74f8629381998f92c060e1763a2) # reset_artifacts: -10 # build_abe binutils: -9 # build_llvm: -5 # build_abe qemu: -2 # linux_n_obj: 19722 # First few build errors in logs:
from (for last_good == 62fb9874f5da54fdb243003b386128037319b219) # reset_artifacts: -10 # build_abe binutils: -9 # build_llvm: -5 # build_abe qemu: -2 # linux_n_obj: 19795 # linux build successful: all
Artifacts of last_good build: https://ci.linaro.org/job/tcwg_kernel-llvm-bisect-llvm-master-aarch64-mainli... Artifacts of first_bad build: https://ci.linaro.org/job/tcwg_kernel-llvm-bisect-llvm-master-aarch64-mainli... Build top page/logs: https://ci.linaro.org/job/tcwg_kernel-llvm-bisect-llvm-master-aarch64-mainli...
00:04:11 drivers/firmware/iscsi_ibft.c:868:15: error: implicit declaration of function 'isa_bus_to_virt' [-Werror,-Wimplicit-function-declaration] 00:04:11 ibft_addr = isa_bus_to_virt(ibft_phys_addr); 00:04:11 ^ 00:04:11 drivers/firmware/iscsi_ibft.c:868:13: warning: incompatible integer to pointer conversion assigning to 'struct acpi_table_ibft *' from 'int' [-Wint-conversion] 00:04:11 ibft_addr = isa_bus_to_virt(ibft_phys_addr); 00:04:11 ^ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Should be fixed as of commit 799206c1302e ("iscsi_ibft: Fix isa_bus_to_virt not working under ARM").
https://lore.kernel.org/r/20210901164722.GA2100627@roeck-us.net/ https://lore.kernel.org/r/YTJ5jFf9iBC50pMs@localhost.localdomain/
Is there any way to get these emails shifted from clang-built-linux@googlegroups.com to llvm@lists.linux.dev? They are very helpful but we'd like to have history of them on lore.kernel.org :)
Cheers, Nathan