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 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
