/* * 32-bit test to check vDSO mremap. * * Copyright (c) 2016 Dmitry Safonov * Suggested-by: Andrew Lutomirski * * This program is free software; you can redistribute it and/or modify * it under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. */ /* * Can be built statically: * gcc -Os -Wall -static -m32 test_mremap_vdso.c */ #define _GNU_SOURCE #include #include #include #include #include #include #include #include #define PAGE_SIZE 4096 static int try_to_remap(void *vdso_addr, unsigned long size) { void *dest_addr, *new_addr; /* Searching for memory location where to remap */ dest_addr = mmap(0, size, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); if (dest_addr == MAP_FAILED) { printf("[WARN]\tmmap failed (%d): %m\n", errno); return 0; } printf("[NOTE]\tMoving vDSO: [%p, %#lx] -> [%p, %#lx]\n", vdso_addr, (unsigned long)vdso_addr + size, dest_addr, (unsigned long)dest_addr + size); fflush(stdout); new_addr = mremap(vdso_addr, size, size, MREMAP_FIXED|MREMAP_MAYMOVE, dest_addr); if ((unsigned long)new_addr == (unsigned long)-1) { munmap(dest_addr, size); if (errno == EINVAL) { printf("[NOTE]\tvDSO partial move failed, will try with bigger size\n"); return -1; /* Retry with larger */ } printf("[FAIL]\tmremap failed (%d): %m\n", errno); return 1; } return 0; } int main(int argc, char **argv, char **envp) { pid_t child; child = fork(); if (child == -1) { printf("[WARN]\tfailed to fork (%d): %m\n", errno); return 1; } if (child == 0) { unsigned long vdso_size = PAGE_SIZE; unsigned long auxval; int ret = -1; auxval = getauxval(AT_SYSINFO_EHDR); printf("\tAT_SYSINFO_EHDR is %#lx\n", auxval); if (!auxval || auxval == -ENOENT) { printf("[WARN]\tgetauxval failed\n"); return 0; } /* Simpler than parsing ELF header */ while (ret < 0) { ret = try_to_remap((void *)auxval, vdso_size); vdso_size += PAGE_SIZE; } /* Glibc is likely to explode now - exit with raw syscall */ asm volatile ("int $0x80" : : "a" (__NR_exit), "b" (!!ret)); } else { int status; if (waitpid(child, &status, 0) != child || !WIFEXITED(status)) { printf("[FAIL]\tmremap() of the vDSO does not work on this kernel!\n"); return 1; } else if (WEXITSTATUS(status) != 0) { printf("[FAIL]\tChild failed with %d\n", WEXITSTATUS(status)); return 1; } printf("[OK]\n"); } return 0; } 74b02d0a143'>fs/xfs/xfs_sysfs.c
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authorBjorn Helgaas <bhelgaas@google.com>2017-01-27 15:00:45 -0600
committerBjorn Helgaas <bhelgaas@google.com>2017-01-27 15:00:45 -0600
commit030305d69fc6963c16003f50d7e8d74b02d0a143 (patch)
tree363a4e34d199178769b7e7eeb26ea2620a55847b /fs/xfs/xfs_sysfs.c
parent4d191b1b63c209e37bf27938ef365244d3c41084 (diff)
PCI/ASPM: Handle PCI-to-PCIe bridges as roots of PCIe hierarchies
In a struct pcie_link_state, link->root points to the pcie_link_state of the root of the PCIe hierarchy. For the topmost link, this points to itself (link->root = link). For others, we copy the pointer from the parent (link->root = link->parent->root). Previously we recognized that Root Ports originated PCIe hierarchies, but we treated PCI/PCI-X to PCIe Bridges as being in the middle of the hierarchy, and when we tried to copy the pointer from link->parent->root, there was no parent, and we dereferenced a NULL pointer: BUG: unable to handle kernel NULL pointer dereference at 0000000000000090 IP: [<ffffffff9e424350>] pcie_aspm_init_link_state+0x170/0x820 Recognize that PCI/PCI-X to PCIe Bridges originate PCIe hierarchies just like Root Ports do, so link->root for these devices should also point to itself. Fixes: 51ebfc92b72b ("PCI: Enumerate switches below PCI-to-PCIe bridges") Link: https://bugzilla.kernel.org/show_bug.cgi?id=193411 Link: https://bugzilla.opensuse.org/show_bug.cgi?id=1022181 Tested-by: lists@ssl-mail.com Tested-by: Jayachandran C. <jnair@caviumnetworks.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> CC: stable@vger.kernel.org # v4.2+
Diffstat (limited to 'fs/xfs/xfs_sysfs.c')