kernel/git/stable/linux.git/arch/parisc, branch linux-4.6.y

parisc: Fix pagefault crash in unaligned __get_user() call

2016-06-24T17:22:03+00:00

commit 8b78f260887df532da529f225c49195d18fef36b upstream. One of the debian buildd servers had this crash in the syslog without any other information: Unaligned handler failed, ret = -2 clock_adjtime (pid 22578): Unaligned data reference (code 28) CPU: 1 PID: 22578 Comm: clock_adjtime Tainted: G E 4.5.0-2-parisc64-smp #1 Debian 4.5.4-1 task: 000000007d9960f8 ti: 00000001bde7c000 task.ti: 00000001bde7c000 YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI PSW: 00001000000001001111100000001111 Tainted: G E r00-03 000000ff0804f80f 00000001bde7c2b0 00000000402d2be8 00000001bde7c2b0 r04-07 00000000409e1fd0 00000000fa6f7fff 00000001bde7c148 00000000fa6f7fff r08-11 0000000000000000 00000000ffffffff 00000000fac9bb7b 000000000002b4d4 r12-15 000000000015241c 000000000015242c 000000000000002d 00000000fac9bb7b r16-19 0000000000028800 0000000000000001 0000000000000070 00000001bde7c218 r20-23 0000000000000000 00000001bde7c210 0000000000000002 0000000000000000 r24-27 0000000000000000 0000000000000000 00000001bde7c148 00000000409e1fd0 r28-31 0000000000000001 00000001bde7c320 00000001bde7c350 00000001bde7c218 sr00-03 0000000001200000 0000000001200000 0000000000000000 0000000001200000 sr04-07 0000000000000000 0000000000000000 0000000000000000 0000000000000000 IASQ: 0000000000000000 0000000000000000 IAOQ: 00000000402d2e84 00000000402d2e88 IIR: 0ca0d089 ISR: 0000000001200000 IOR: 00000000fa6f7fff CPU: 1 CR30: 00000001bde7c000 CR31: ffffffffffffffff ORIG_R28: 00000002369fe628 IAOQ[0]: compat_get_timex+0x2dc/0x3c0 IAOQ[1]: compat_get_timex+0x2e0/0x3c0 RP(r2): compat_get_timex+0x40/0x3c0 Backtrace: [<00000000402d4608>] compat_SyS_clock_adjtime+0x40/0xc0 [<0000000040205024>] syscall_exit+0x0/0x14 This means the userspace program clock_adjtime called the clock_adjtime() syscall and then crashed inside the compat_get_timex() function. Syscalls should never crash programs, but instead return EFAULT. The IIR register contains the executed instruction, which disassebles into "ldw 0(sr3,r5),r9". This load-word instruction is part of __get_user() which tried to read the word at %r5/IOR (0xfa6f7fff). This means the unaligned handler jumped in. The unaligned handler is able to emulate all ldw instructions, but it fails if it fails to read the source e.g. because of page fault. The following program reproduces the problem: #define _GNU_SOURCE #include #include #include int main(void) { /* allocate 8k */ char *ptr = mmap(NULL, 2*4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0); /* free second half (upper 4k) and make it invalid. */ munmap(ptr+4096, 4096); /* syscall where first int is unaligned and clobbers into invalid memory region */ /* syscall should return EFAULT */ return syscall(__NR_clock_adjtime, 0, ptr+4095); } To fix this issue we simply need to check if the faulting instruction address is in the exception fixup table when the unaligned handler failed. If it is, call the fixup routine instead of crashing. While looking at the unaligned handler I found another issue as well: The target register should not be modified if the handler was unsuccessful. Signed-off-by: Helge Deller Signed-off-by: Greg Kroah-Hartman

parisc: fix a bug when syscall number of tracee is __NR_Linux_syscalls

2016-05-06T13:09:07+00:00

Do not load one entry beyond the end of the syscall table when the syscall number of a traced process equals to __NR_Linux_syscalls. Similar bug with regular processes was fixed by commit 3bb457af4fa8 ("[PARISC] Fix bug when syscall nr is __NR_Linux_syscalls"). This bug was found by strace test suite. Cc: stable@vger.kernel.org Signed-off-by: Dmitry V. Levin Acked-by: Helge Deller Signed-off-by: Helge Deller

Merge branch 'parisc-4.6-4' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

2016-04-15T21:51:45+00:00

Pull parisc ftrace fixes from Helge Deller: "This is (most likely) the last pull request for v4.6 for the parisc architecture. It fixes the FTRACE feature for parisc, which is horribly broken since quite some time and doesn't even compile. This patch just fixes the bare minimum (it actually removes more lines than it adds), so that the function tracer works again on 32- and 64bit kernels. I've queued up additional patches on top of this patch which e.g. add the syscall tracer, but those have to wait for the merge window for v4.7." * 'parisc-4.6-4' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux: parisc: Fix ftrace function tracer

parisc: Fix ftrace function tracer

2016-04-14T15:47:19+00:00

Fix the FTRACE function tracer for 32- and 64-bit kernel. The former code was horribly broken. Reimplement most coding in assembly and utilize optimizations, e.g. put mcount() and ftrace_stub() into one L1 cacheline. Signed-off-by: Helge Deller

parisc: Update comment regarding relative extable support

2016-04-08T20:14:26+00:00

Update the comment to reflect the changes of commit 0de7985 (parisc: Use generic extable search and sort routines). Signed-off-by: Helge Deller

parisc: Unbreak handling exceptions from kernel modules

2016-04-08T20:14:14+00:00

Handling exceptions from modules never worked on parisc. It was just masked by the fact that exceptions from modules don't happen during normal use. When a module triggers an exception in get_user() we need to load the main kernel dp value before accessing the exception_data structure, and afterwards restore the original dp value of the module on exit. Noticed-by: Mikulas Patocka Signed-off-by: Helge Deller Cc: stable@vger.kernel.org

parisc: Fix kernel crash with reversed copy_from_user()

2016-04-08T20:14:04+00:00

The kernel module testcase (lib/test_user_copy.c) exhibited a kernel crash on parisc if the parameters for copy_from_user were reversed ("illegal reversed copy_to_user" testcase). Fix this potential crash by checking the fault handler if the faulting address is in the exception table. Signed-off-by: Helge Deller Cc: stable@vger.kernel.org Cc: Kees Cook

parisc: Avoid function pointers for kernel exception routines

2016-04-08T20:13:45+00:00

We want to avoid the kernel module loader to create function pointers for the kernel fixup routines of get_user() and put_user(). Changing the external reference from function type to int type fixes this. This unbreaks exception handling for get_user() and put_user() when called from a kernel module. Signed-off-by: Helge Deller Cc: stable@vger.kernel.org

parisc: Handle R_PARISC_PCREL32 relocations in kernel modules

2016-04-08T20:10:35+00:00

Commit 0de7985 (parisc: Use generic extable search and sort routines) changed the exception tables to use 32bit relative offsets. This patch now adds support to the kernel module loader to handle such R_PARISC_PCREL32 relocations for 32- and 64-bit modules. Signed-off-by: Helge Deller

mm, fs: remove remaining PAGE_CACHE_* and page_cache_{get,release} usage

2016-04-04T17:41:08+00:00

Mostly direct substitution with occasional adjustment or removing outdated comments. Signed-off-by: Kirill A. Shutemov Acked-by: Michal Hocko Signed-off-by: Linus Torvalds