Messages in this thread Patch in this message | | | Date | Sat, 18 Jan 2003 02:44:56 -0800 | From | Andrew Morton <> | Subject | Re: recent change to exit_mmap |
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Anton Blanchard <anton@samba.org> wrote: > > > > On seconds thoughts... > > > > Are the first two SET_PERSONALITY() calls in there actually doing anything? > > Perhaps you're right, and we only need the one at line 615, whcih is in the > > right place? > > Sounds good. The following patch tests out OK. > > Anton > > ===== fs/binfmt_elf.c 1.34 vs edited ===== > --- 1.34/fs/binfmt_elf.c Mon Nov 25 19:59:02 2002 > +++ edited/fs/binfmt_elf.c Sat Jan 18 18:16:52 2003 > @@ -536,8 +536,6 @@ > strcmp(elf_interpreter,"/usr/lib/ld.so.1") == 0) > ibcs2_interpreter = 1; > > - SET_PERSONALITY(elf_ex, ibcs2_interpreter); > - > interpreter = open_exec(elf_interpreter); > retval = PTR_ERR(interpreter); > if (IS_ERR(interpreter)) > @@ -578,9 +576,6 @@ > // printk(KERN_WARNING "ELF: Ambiguous type, using ELF\n"); > interpreter_type = INTERPRETER_ELF; > } > - } else { > - /* Executables without an interpreter also need a personality */ > - SET_PERSONALITY(elf_ex, ibcs2_interpreter); > }
Unfortunately it isn't right. See, we set the peronality prior to looking up the elf interpreter because different types of executables can have different filesystem namespaces. open_exec() needs it. The IBCS stuff needs this, as well as (thanks davem):
"When we have a personality like "SunOS" or whatever, we allow the usage of an alternate '/' for file lookups, it trumps whatever would be found in the normal /, so we could put the SunOS ld.so under /emul/SunOS/lib for example using an emulation alternative-root of /emul/SunOS"
And we can't dump the currect exec image until we've determined that the interpreter is available.
So it's all a bit of a stew. We're back to the original patch. Could you please test it? (This includes the ia64 bit)
diff -puN mm/mmap.c~exit_mmap-fix mm/mmap.c --- 25/mm/mmap.c~exit_mmap-fix 2003-01-17 22:35:13.000000000 -0800 +++ 25-akpm/mm/mmap.c 2003-01-17 22:41:10.000000000 -0800 @@ -1379,6 +1379,22 @@ void build_mmap_rb(struct mm_struct * mm } } +/* + * During exit_mmap, TASK_SIZE is not a reliable indication of the virtual + * size of the mm which is being torn down. Because on the exec() path, this + * process may have switched its personality from 64-bit to 32-bit prior to + * calling exit_mmap(). So TASK_SIZE returns a value suitable for a 32-bit + * process, and not the 64-bit process whose mm we need to empty. + * + * So what we do is to always unmap the largest virtual address space which + * the architecture supports. unmap_vmas() will then unmap every VMA in the + * mm, which is what we want to happen here. + */ + +#ifndef TASK_SIZE_MAX +#define TASK_SIZE_MAX TASK_SIZE +#endif + /* Release all mmaps. */ void exit_mmap(struct mm_struct *mm) { @@ -1395,7 +1411,7 @@ void exit_mmap(struct mm_struct *mm) tlb = tlb_gather_mmu(mm, 1); flush_cache_mm(mm); mm->map_count -= unmap_vmas(&tlb, mm, mm->mmap, 0, - TASK_SIZE, &nr_accounted); + TASK_SIZE_MAX, &nr_accounted); vm_unacct_memory(nr_accounted); BUG_ON(mm->map_count); /* This is just debugging */ clear_page_tables(tlb, FIRST_USER_PGD_NR, USER_PTRS_PER_PGD); diff -puN include/asm-ppc64/processor.h~exit_mmap-fix include/asm-ppc64/processor.h --- 25/include/asm-ppc64/processor.h~exit_mmap-fix 2003-01-17 22:41:32.000000000 -0800 +++ 25-akpm/include/asm-ppc64/processor.h 2003-01-17 22:42:03.000000000 -0800 @@ -630,6 +630,7 @@ extern struct task_struct *last_task_use #define TASK_SIZE (test_thread_flag(TIF_32BIT) ? \ TASK_SIZE_USER32 : TASK_SIZE_USER64) +#define TASK_SIZE_MAX TASK_SIZE_USER64 #endif /* __KERNEL__ */ diff -puN include/asm-ia64/processor.h~exit_mmap-fix include/asm-ia64/processor.h --- 25/include/asm-ia64/processor.h~exit_mmap-fix 2003-01-17 22:46:08.000000000 -0800 +++ 25-akpm/include/asm-ia64/processor.h 2003-01-17 22:47:19.000000000 -0800 @@ -39,6 +39,12 @@ #define TASK_SIZE (current->thread.task_size) /* + * This determines the virtual address space which must be torn down + * during exec. + * +#define TASK_SIZE_MAX DEFAULT_TASK_SIZE + +/* * This decides where the kernel will search for a free chunk of vm * space during mmap's. */ _
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