This is a note to let you know that I've just added the patch titled
s390/disassembler: increase show_code buffer size
to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: s390-disassembler-increase-show_code-buffer-size.patch and it can be found in the queue-3.18 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From b192571d1ae375e0bbe0aa3ccfa1a3c3704454b9 Mon Sep 17 00:00:00 2001
From: Vasily Gorbik gor@linux.vnet.ibm.com Date: Wed, 15 Nov 2017 14:15:36 +0100 Subject: s390/disassembler: increase show_code buffer size
From: Vasily Gorbik gor@linux.vnet.ibm.com
commit b192571d1ae375e0bbe0aa3ccfa1a3c3704454b9 upstream.
Current buffer size of 64 is too small. objdump shows that there are instructions which would require up to 75 bytes buffer (with current formating). 128 bytes "ought to be enough for anybody".
Also replaces 8 spaces with a single tab to reduce the memory footprint.
Fixes the following KASAN finding:
BUG: KASAN: stack-out-of-bounds in number+0x3fe/0x538 Write of size 1 at addr 000000005a4a75a0 by task bash/1282
CPU: 1 PID: 1282 Comm: bash Not tainted 4.14.0+ #215 Hardware name: IBM 2964 N96 702 (z/VM 6.4.0) Call Trace: ([<000000000011eeb6>] show_stack+0x56/0x88) [<0000000000e1ce1a>] dump_stack+0x15a/0x1b0 [<00000000004e2994>] print_address_description+0xf4/0x288 [<00000000004e2cf2>] kasan_report+0x13a/0x230 [<0000000000e38ae6>] number+0x3fe/0x538 [<0000000000e3dfe4>] vsnprintf+0x194/0x948 [<0000000000e3ea42>] sprintf+0xa2/0xb8 [<00000000001198dc>] print_insn+0x374/0x500 [<0000000000119346>] show_code+0x4ee/0x538 [<000000000011f234>] show_registers+0x34c/0x388 [<000000000011f2ae>] show_regs+0x3e/0xa8 [<000000000011f502>] die+0x1ea/0x2e8 [<0000000000138f0e>] do_no_context+0x106/0x168 [<0000000000139a1a>] do_protection_exception+0x4da/0x7d0 [<0000000000e55914>] pgm_check_handler+0x16c/0x1c0 [<000000000090639e>] sysrq_handle_crash+0x46/0x58 ([<0000000000000007>] 0x7) [<00000000009073fa>] __handle_sysrq+0x102/0x218 [<0000000000907c06>] write_sysrq_trigger+0xd6/0x100 [<000000000061d67a>] proc_reg_write+0xb2/0x128 [<0000000000520be6>] __vfs_write+0xee/0x368 [<0000000000521222>] vfs_write+0x21a/0x278 [<000000000052156a>] SyS_write+0xda/0x178 [<0000000000e555cc>] system_call+0xc4/0x270
The buggy address belongs to the page: page:000003d1016929c0 count:0 mapcount:0 mapping: (null) index:0x0 flags: 0x0() raw: 0000000000000000 0000000000000000 0000000000000000 ffffffff00000000 raw: 0000000000000100 0000000000000200 0000000000000000 0000000000000000 page dumped because: kasan: bad access detected
Memory state around the buggy address: 000000005a4a7480: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 000000005a4a7500: 00 00 00 00 00 00 00 00 f2 f2 f2 f2 00 00 00 00
000000005a4a7580: 00 00 00 00 f3 f3 f3 f3 00 00 00 00 00 00 00 00
^ 000000005a4a7600: 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 f8 f8 000000005a4a7680: f2 f2 f2 f2 f2 f2 f8 f8 f2 f2 f3 f3 f3 f3 00 00 ==================================================================
Signed-off-by: Vasily Gorbik gor@linux.vnet.ibm.com Signed-off-by: Martin Schwidefsky schwidefsky@de.ibm.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- arch/s390/kernel/dis.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/s390/kernel/dis.c +++ b/arch/s390/kernel/dis.c @@ -1997,7 +1997,7 @@ void show_code(struct pt_regs *regs) { char *mode = user_mode(regs) ? "User" : "Krnl"; unsigned char code[64]; - char buffer[64], *ptr; + char buffer[128], *ptr; mm_segment_t old_fs; unsigned long addr; int start, end, opsize, hops, i; @@ -2060,7 +2060,7 @@ void show_code(struct pt_regs *regs) start += opsize; printk(buffer); ptr = buffer; - ptr += sprintf(ptr, "\n "); + ptr += sprintf(ptr, "\n\t "); hops++; } printk("\n");
Patches currently in stable-queue which might be from gor@linux.vnet.ibm.com are
queue-3.18/s390-disassembler-increase-show_code-buffer-size.patch