Messages in this thread | | | Date | Tue, 29 Mar 2011 22:24:21 +0200 | Subject | Re: [regression v2.6.38] Re: [PATCH v2] brk: fix min_brk lower bound computation for COMPAT_BRK | From | Geert Uytterhoeven <> |
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Hi Jiri,
On Mon, Mar 28, 2011 at 16:20, Jiri Kosina <jkosina@suse.cz> wrote: > On Sat, 26 Mar 2011, Geert Uytterhoeven wrote: >> >> | RAMDISK: gzip image found at block 0 >> >> | VFS: Mounted root (ext2 filesystem) readonly on device 1:0. >> >> | warning: process `update' used the obsolete bdflush system call >> >> | Fix your initscripts? >> >> | init: cannot open inittab >> >> | Kernel panic - not syncing: Attempted to kill init!
> Hmm, I think we'd need some refresh on what the ancient libc5-based > binaries are actually doing. > > Could you please send me strace of this application (restricting it to > brk()/mmap() calls should be enough).
I managed to reproduce it inside ARAnyM, by chrooting into the ramdisk image. After adding strace, "strace /sbin/init" for the success case gives:
old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xc0004000 old_mmap(NULL, 578, PROT_READ, MAP_SHARED, 3, 0) = 0xc0007000 old_mmap(NULL, 663552, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xc0008000 old_mmap(0xc0008000, 426908, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED, 3, 0) = 0xc0008000 old_mmap(0xc0072000, 24256, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 3, 0x68000) = 0xc0072000 old_mmap(0xc0078000, 204696, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xc0078000 brk(0x80005c8e) = 0x80005c8e brk(0x80006000) = 0x80006000 old_mmap(NULL, 1024, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xc0007000
For the failure case:
old_mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xc0004000 old_mmap(NULL, 578, PROT_READ, MAP_SHARED, 3, 0) = 0xc0007000 old_mmap(NULL, 663552, PROT_NONE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xc0008000 old_mmap(0xc0008000, 426908, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_FIXED, 3, 0) = 0xc0008000 old_mmap(0xc0072000, 24256, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED, 3, 0x68000) = 0xc0072000 old_mmap(0xc0078000, 204696, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xc0078000 brk(0x80005c8e) = 0x80006000
Major difference:
-brk(0x80005c8e) = 0x80005c8e -brk(0x80006000) = 0x80006000 -open("/etc/inittab", O_RDONLY) = 3 -fstat(3, {st_mode=S_IFREG|0644, st_size=140, ...}) = 0 -old_mmap(NULL, 1024, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xc0007000 -read(3, "tty1:console:/sbin/getty 9600 tt"..., 1024) = 140 -read(3, "", 1024) = 0 +brk(0x80005c8e) = 0x80006000 +open("/dev/console", O_WRONLY) = 3 +write(3, "init: ", 6) = 6 +write(3, "cannot open inittab\n", 20) = 20 close(3) = 0
Seems like the binary doesn't like brk() rounding up the requested value to the next page...
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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