On Fri 26-01-18 18:04:27, Anshuman Khandual wrote: [...] > I tried to instrument mmap_region() for a single instance of 'sed' > binary and traced all it's VMA creation. But there is no trace when > that 'anon' VMA got created which suddenly shows up during subsequent > elf_map() call eventually failing it. Please note that the following > VMA was never created through call into map_region() in the process > which is strange. Could you share your debugging patch? > ================================================================= > [ 9.076867] Details for VMA[3] c000001fce42b7c0 > [ 9.076925] vma c000001fce42b7c0 start 0000000010030000 end 0000000010040000 > next c000001fce42b580 prev c000001fce42b880 mm c000001fce40fa00 > prot 8000000000000104 anon_vma (null) vm_ops (null) > pgoff 1003 file (null) private_data (null) > flags: 0x100073(read|write|mayread|maywrite|mayexec|account) > ================================================================= Isn't this vdso or some other special mapping? It is not really an anonymous vma. Please hook into __install_special_mapping > VMA creation for 'sed' binary > ============================= > [ 9.071902] XXX: mm c000001fce40fa00 registered > > [ 9.071971] Total VMAs 2 on MM c000001fce40fa00 > ---- > [ 9.072010] Details for VMA[1] c000001fce42bdc0 > [ 9.072064] vma c000001fce42bdc0 start 0000000010000000 end 0000000010020000 > next c000001fce42b580 prev (null) mm c000001fce40fa00 > prot 8000000000000105 anon_vma (null) vm_ops c008000011ddca18 > pgoff 0 file c000001fe2969a00 private_data (null) > flags: 0x875(read|exec|mayread|maywrite|mayexec|denywrite) This one doesn't have any stack trace either... Yet it is a file mapping obviously. Special mappings shouldn't have any file associated. Strange... -- Michal Hocko SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
