On 10/24/2017 11:06 PM, [email protected] wrote:
From: Ard Biesheuvel <[email protected]>
merged to 4.12 Bruce
Instead of passing each start address into is_vmalloc_or_module_addr() to decide whether it falls into either the VMALLOC or the MODULES region, we can simply check the type field of the current kcore_list entry, since it will be set to KCORE_VMALLOC based on exactly the same conditions. As a bonus, when reading the KCORE_TEXT region on architectures that have one, this will avoid using vread() on the region if it happens to intersect with a KCORE_VMALLOC region. This is due the fact that the KCORE_TEXT region is the first one to be added to the kcore region list. Reported-by: Tan Xiaojun <[email protected]> Tested-by: Tan Xiaojun <[email protected]> Tested-by: Mark Rutland <[email protected]> Acked-by: Mark Rutland <[email protected]> Reviewed-by: Laura Abbott <[email protected]> Reviewed-by: Jiri Olsa <[email protected]> Signed-off-by: Ard Biesheuvel <[email protected]> Signed-off-by: Will Deacon <[email protected]> [ To fix following Call Trace when accessing /proc/kcore [ 3637.649161] Call trace: [ 3637.649561] Exception stack(0xffffffc01d5dfaf0 to 0xffffffc01d5dfc20) [ 3637.650306] fae0: ffffff80085ff800 0000008000000000 [ 3637.651183] fb00: ffffffc01d5dfcc0 ffffff80081d0228 ffffffc01d5f4b80 ffffffc01ffe0050 [ 3637.652091] fb20: ffffffc01ffe0050 ffffffc01d5f4b80 0000034ef3b32e60 ffffff80089789a0 [ 3637.652970] fb40: ffffff800871b124 ffffffc01d5f1e60 ffffffc01d5dfb90 ffffff80080d6b1c [ 3637.653848] fb60: ffffffc01ffe0000 ffffffc01d5f4b00 ffffffc01ffe0050 ffffffc01d5f4b80 [ 3637.654733] fb80: ffffff800895d000 ffffffc01d5f4b80 00c0000040400791 ffffffc01fffe210 [ 3637.655600] fba0: 0000000040000000 ffffff80089c8ac8 0000000000000004 0000000000001f0b [ 3637.656481] fbc0: 0000000000000800 ffffff80089c8ac8 0000000000000000 0000000000000800 [ 3637.657353] fbe0: 0000007fd127f1e0 0000000000000012 1a13110001000415 00000016170f120a [ 3637.658231] fc00: 0000000000000012 0000000000000011 ffffff80081f9120 0000007fa8d49f28 [ 3637.659130] [<ffffff80081d0228>] vmalloc_to_page+0xb8/0xd0 [ 3637.659811] [<ffffff80081d37d4>] vread+0x1a4/0x2c0 [ 3637.660420] [<ffffff8008274124>] read_kcore+0x2ac/0x3d8 [ 3637.661052] [<ffffff8008265554>] proc_reg_read+0x8c/0xd0 [ 3637.661694] [<ffffff80081f66a0>] __vfs_read+0x48/0x80 [ 3637.662313] [<ffffff80081f7b7c>] vfs_read+0x8c/0x128 [ 3637.662914] [<ffffff80081f9174>] SyS_read+0x54/0xb0 [ 3637.663512] [<ffffff8008083730>] el0_svc_naked+0x24/0x28 ] Signed-off-by: He Zhe <[email protected]> --- fs/proc/kcore.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c index 4ee5527..45629f4 100644 --- a/fs/proc/kcore.c +++ b/fs/proc/kcore.c @@ -504,7 +504,7 @@ read_kcore(struct file *file, char __user *buffer, size_t buflen, loff_t *fpos) if (&m->list == &kclist_head) { if (clear_user(buffer, tsz)) return -EFAULT; - } else if (is_vmalloc_or_module_addr((void *)start)) { + } else if (m->type == KCORE_VMALLOC) { vread(buf, (char *)start, tsz); /* we have to zero-fill user buffer even if no read */ if (copy_to_user(buffer, buf, tsz))
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