On Wed, Feb 27, 2019 at 1:35 PM Christophe Leroy <christophe.leroy@xxxxxx> wrote: > > > > On 02/27/2019 08:34 AM, Dmitry Vyukov wrote: > > On Wed, Feb 27, 2019 at 9:25 AM Christophe Leroy > > <christophe.leroy@xxxxxx> wrote: > >> > >> With version v8 of the series implementing KASAN on 32 bits powerpc > >> (https://patchwork.ozlabs.org/project/linuxppc-dev/list/?series=94309), > >> I'm now able to activate KASAN on a mac99 is QEMU. > >> > >> Then I get the following reports at startup. Which of the two reports I > >> get seems to depend on the option used to build the kernel, but for a > >> given kernel I always get the same report. > >> > >> Is that a real bug, in which case how could I spot it ? Or is it > >> something wrong in my implementation of KASAN ? > > > > What is the state of your source tree? > > Please pass output through some symbolization script, function offsets > > are not too useful. > > There was some in scripts/ dir IIRC, but here is another one (though, > > never tested on powerpc): > > https://github.com/google/sanitizers/blob/master/address-sanitizer/tools/kasan_symbolize.py > > I get the following. It doesn't seem much interesting, does it ? Yes, it does not seem to work for powerpc32. Then please pass addresses through addr2line -fi. > ================================================================== > BUG: KASAN: stack-out-of-bounds in[< none >] > memchr+0x24/0x74 lib/string.c:958 > Read of size 1 at addr c0ecdd40 by task swapper/0 > > CPU: 0 PID: 0 Comm: swapper Not tainted 5.0.0-rc7+ #1142 > Call Trace: > [c0e9dca0] [c01c42c0] print_address_description+0x64/0x2bc (unreliable) > [c0e9dcd0] [c01c46a4] kasan_report+0xfc/0x180 > [c0e9dd10] [c0895150] memchr+0x24/0x74 > [c0e9dd30] [c00a9e58] msg_print_text+0x124/0x574 > [c0e9dde0] [c00ab730] console_unlock+0x114/0x4f8 > [c0e9de40] [c00adc80] vprintk_emit+0x188/0x1c4 > [c0e9de80] [c00ae3e4] printk+0xa8/0xcc > [c0e9df20] [c0c27e44] early_irq_init+0x38/0x108 > [c0e9df50] [c0c15434] start_kernel+0x310/0x488 > [c0e9dff0] [00003484] 0x3484 > > The buggy address belongs to the variable: > [< none >] __log_buf+0xec0/0x4020 > arch/powerpc/kernel/head_32.S:? > The buggy address belongs to the page: > page:c6eac9a0 count:1 mapcount:0 mapping:00000000 index:0x0 > flags: 0x1000(reserved) > raw: 00001000 c6eac9a4 c6eac9a4 00000000 00000000 00000000 ffffffff 00000001 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > c0ecdc00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > c0ecdc80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >c0ecdd00: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00 > ^ > c0ecdd80: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 > c0ecde00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > ================================================================== > > > Christophe > > > > > > > > >> I checked that after kasan_init(), the entire shadow memory is full of 0 > >> only. > >> > >> I also made a try with the strong STACK_PROTECTOR compiled in, but no > >> difference and nothing detected by the stack protector. > >> > >> ================================================================== > >> BUG: KASAN: stack-out-of-bounds in memchr+0x24/0x74 > >> Read of size 1 at addr c0ecdd40 by task swapper/0 > >> > >> CPU: 0 PID: 0 Comm: swapper Not tainted 5.0.0-rc7+ #1133 > >> Call Trace: > >> [c0e9dca0] [c01c42a0] print_address_description+0x64/0x2bc (unreliable) > >> [c0e9dcd0] [c01c4684] kasan_report+0xfc/0x180 > >> [c0e9dd10] [c089579c] memchr+0x24/0x74 > >> [c0e9dd30] [c00a9e38] msg_print_text+0x124/0x574 > >> [c0e9dde0] [c00ab710] console_unlock+0x114/0x4f8 > >> [c0e9de40] [c00adc60] vprintk_emit+0x188/0x1c4 > >> --- interrupt: c0e9df00 at 0x400f330 > >> LR = init_stack+0x1f00/0x2000 > >> [c0e9de80] [c00ae3c4] printk+0xa8/0xcc (unreliable) > >> [c0e9df20] [c0c28e44] early_irq_init+0x38/0x108 > >> [c0e9df50] [c0c16434] start_kernel+0x310/0x488 > >> [c0e9dff0] [00003484] 0x3484 > >> > >> The buggy address belongs to the variable: > >> __log_buf+0xec0/0x4020 > >> The buggy address belongs to the page: > >> page:c6eac9a0 count:1 mapcount:0 mapping:00000000 index:0x0 > >> flags: 0x1000(reserved) > >> raw: 00001000 c6eac9a4 c6eac9a4 00000000 00000000 00000000 ffffffff 00000001 > >> page dumped because: kasan: bad access detected > >> > >> Memory state around the buggy address: > >> c0ecdc00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >> c0ecdc80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >> >c0ecdd00: 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00 > >> ^ > >> c0ecdd80: f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 > >> c0ecde00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >> ================================================================== > >> > >> ================================================================== > >> BUG: KASAN: stack-out-of-bounds in pmac_nvram_init+0x1ec/0x600 > >> Read of size 1 at addr f6f37de0 by task swapper/0 > >> > >> CPU: 0 PID: 0 Comm: swapper Not tainted 5.0.0-rc7+ #1134 > >> Call Trace: > >> [c0ff7d60] [c01fe808] print_address_description+0x6c/0x2b0 (unreliable) > >> [c0ff7d90] [c01fe4fc] kasan_report+0x13c/0x1ac > >> [c0ff7dd0] [c0d34324] pmac_nvram_init+0x1ec/0x600 > >> [c0ff7ef0] [c0d31148] pmac_setup_arch+0x280/0x308 > >> [c0ff7f20] [c0d2c30c] setup_arch+0x250/0x280 > >> [c0ff7f50] [c0d26354] start_kernel+0xb8/0x4d8 > >> [c0ff7ff0] [00003484] 0x3484 > >> > >> > >> Memory state around the buggy address: > >> f6f37c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >> f6f37d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >> >f6f37d80: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 > >> ^ > >> f6f37e00: 00 00 00 00 f2 f2 f2 f2 00 00 00 00 f2 f2 f2 f2 > >> f6f37e80: 00 00 01 f2 00 00 00 00 00 00 00 00 00 00 00 00 > >> ================================================================== > >> > >> ================================================================== > >> BUG: KASAN: stack-out-of-bounds in memchr+0xa0/0xac > >> Read of size 1 at addr c17cdd30 by task swapper/0 > >> > >> CPU: 0 PID: 0 Comm: swapper Not tainted 5.0.0-rc7+ #1135 > >> Call Trace: > >> [c179dc90] [c032fe28] print_address_description+0x64/0x2bc (unreliable) > >> [c179dcc0] [c033020c] kasan_report+0xfc/0x180 > >> [c179dd00] [c115ef50] memchr+0xa0/0xac > >> [c179dd20] [c01297f8] msg_print_text+0xc8/0x67c > >> [c179ddd0] [c012bc8c] console_unlock+0x17c/0x818 > >> [c179de40] [c012f420] vprintk_emit+0x188/0x1c4 > >> --- interrupt: c179df30 at 0x400def0 > >> LR = init_stack+0x1ef0/0x2000 > >> [c179de80] [c012fff0] printk+0xa8/0xcc (unreliable) > >> [c179df20] [c150b4b8] early_irq_init+0x38/0x108 > >> [c179df50] [c14ef7f8] start_kernel+0x30c/0x530 > >> [c179dff0] [00003484] 0x3484 > >> > >> The buggy address belongs to the variable: > >> __log_buf+0xeb0/0x4020 > >> The buggy address belongs to the page: > >> page:c6ebe9a0 count:1 mapcount:0 mapping:00000000 index:0x0 > >> flags: 0x1000(reserved) > >> raw: 00001000 c6ebe9a4 c6ebe9a4 00000000 00000000 00000000 ffffffff 00000001 > >> page dumped because: kasan: bad access detected > >> > >> Memory state around the buggy address: > >> c17cdc00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >> c17cdc80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >> >c17cdd00: 00 00 00 00 00 00 f1 f1 f1 f1 00 00 00 00 f3 f3 > >> ^ > >> c17cdd80: f3 f3 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >> c17cde00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >> ================================================================== > >> > >> ================================================================== > >> BUG: KASAN: stack-out-of-bounds in pmac_nvram_init+0x228/0xae0 > >> Read of size 1 at addr f6f37dd0 by task swapper/0 > >> > >> CPU: 0 PID: 0 Comm: swapper Not tainted 5.0.0-rc7+ #1136 > >> Call Trace: > >> [c1c37d50] [c03f7e88] print_address_description+0x6c/0x2b0 (unreliable) > >> [c1c37d80] [c03f7bd4] kasan_report+0x10c/0x16c > >> [c1c37dc0] [c19879b4] pmac_nvram_init+0x228/0xae0 > >> [c1c37ef0] [c19826bc] pmac_setup_arch+0x578/0x6a8 > >> [c1c37f20] [c19792bc] setup_arch+0x5f4/0x620 > >> [c1c37f50] [c196f898] start_kernel+0xb8/0x588 > >> [c1c37ff0] [00003484] 0x3484 > >> > >> > >> Memory state around the buggy address: > >> f6f37c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >> f6f37d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >> >f6f37d80: 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 00 00 > >> ^ > >> f6f37e00: 01 f2 f2 f2 f2 f2 00 00 00 00 f2 f2 f2 f2 00 00 > >> f6f37e80: 00 00 f3 f3 f3 f3 00 00 00 00 00 00 00 00 00 00 > >> ================================================================== > >> > >> ================================================================== > >> BUG: KASAN: stack-out-of-bounds in pmac_nvram_init+0x1ec/0x5ec > >> Read of size 1 at addr f6f37de0 by task swapper/0 > >> > >> CPU: 0 PID: 0 Comm: swapper Not tainted 5.0.0-rc7+ #1137 > >> Call Trace: > >> [c0fb7d60] [c01f8184] print_address_description+0x6c/0x2b0 (unreliable) > >> [c0fb7d90] [c01f7ed0] kasan_report+0x10c/0x16c > >> [c0fb7dd0] [c0d1dfe8] pmac_nvram_init+0x1ec/0x5ec > >> [c0fb7ef0] [c0d1ae90] pmac_setup_arch+0x280/0x308 > >> [c0fb7f20] [c0d16138] setup_arch+0x250/0x280 > >> [c0fb7f50] [c0d1032c] start_kernel+0xb8/0x4a4 > >> [c0fb7ff0] [00003484] 0x3484 > >> > >> > >> Memory state around the buggy address: > >> f6f37c80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >> f6f37d00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 > >> >f6f37d80: 00 00 00 00 00 00 00 00 00 00 00 00 f1 f1 f1 f1 > >> ^ > >> f6f37e00: 00 00 01 f2 f2 f2 f2 f2 00 00 00 00 f2 f2 f2 f2 > >> f6f37e80: 00 00 00 00 f3 f3 f3 f3 00 00 00 00 00 00 00 00 > >> ================================================================== > >> > >> Thanks > >> Christophe
