On Mon, Dec 08, 2008 at 12:34:52PM +0000, Konstantin Belousov wrote: > Author: kib > Date: Mon Dec 8 12:34:52 2008 > New Revision: 185765 > URL: http://svn.freebsd.org/changeset/base/185765 > > Log: > Change the linprocfs <pid>/maps and procfs <pid>/map handlers to use > sbuf instead of doing uiomove. This allows for reads from non-zero > offsets to work. > > Patch is forward-ported des@' one, and was adopted to current code > by dchagin@ and me. > > Reviewed by: des (linprocfs part) > PR: kern/101453 > MFC after: 1 week > > Modified: > head/sys/compat/linprocfs/linprocfs.c > head/sys/fs/procfs/procfs_map.c
Thanks for Roman Divacky for pointing this out, commit message is wrong.
I specified wrong log file to the svn ci -F switch.
The right commit message is below.
In procfs map handler, and in linprocfs maps handler, do not call
vn_fullpath() while having vm map locked. This is done in anticipation
of the vop_vptocnp commit, that would make vn_fullpath sometime
acquire vnode lock.
Also, in linprocfs, maps handler already acquires vnode lock.
No objections from: des
MFC after: 2 week
>
> Modified: head/sys/compat/linprocfs/linprocfs.c
> ==============================================================================
> --- head/sys/compat/linprocfs/linprocfs.c Mon Dec 8 12:29:30 2008
> (r185764)
> +++ head/sys/compat/linprocfs/linprocfs.c Mon Dec 8 12:34:52 2008
> (r185765)
> @@ -876,10 +876,12 @@ static int
> linprocfs_doprocmaps(PFS_FILL_ARGS)
> {
> vm_map_t map = &p->p_vmspace->vm_map;
> - vm_map_entry_t entry;
> + vm_map_entry_t entry, tmp_entry;
> vm_object_t obj, tobj, lobj;
> - vm_offset_t saved_end;
> + vm_offset_t e_start, e_end;
> vm_ooffset_t off = 0;
> + vm_prot_t e_prot;
> + unsigned int last_timestamp;
> char *name = "", *freename = NULL;
> ino_t ino;
> int ref_count, shadow_count, flags;
> @@ -905,7 +907,9 @@ linprocfs_doprocmaps(PFS_FILL_ARGS)
> freename = NULL;
> if (entry->eflags & MAP_ENTRY_IS_SUB_MAP)
> continue;
> - saved_end = entry->end;
> + e_prot = entry->protection;
> + e_start = entry->start;
> + e_end = entry->end;
> obj = entry->object.vm_object;
> for (lobj = tobj = obj; tobj; tobj = tobj->backing_object) {
> VM_OBJECT_LOCK(tobj);
> @@ -913,6 +917,8 @@ linprocfs_doprocmaps(PFS_FILL_ARGS)
> VM_OBJECT_UNLOCK(lobj);
> lobj = tobj;
> }
> + last_timestamp = map->timestamp;
> + vm_map_unlock_read(map);
> ino = 0;
> if (lobj) {
> off = IDX_TO_OFF(lobj->size);
> @@ -950,10 +956,10 @@ linprocfs_doprocmaps(PFS_FILL_ARGS)
> */
> error = sbuf_printf(sb,
> "%08lx-%08lx %s%s%s%s %08lx %02x:%02x %lu%s%s\n",
> - (u_long)entry->start, (u_long)entry->end,
> - (entry->protection & VM_PROT_READ)?"r":"-",
> - (entry->protection & VM_PROT_WRITE)?"w":"-",
> - (entry->protection & VM_PROT_EXECUTE)?"x":"-",
> + (u_long)e_start, (u_long)e_end,
> + (e_prot & VM_PROT_READ)?"r":"-",
> + (e_prot & VM_PROT_WRITE)?"w":"-",
> + (e_prot & VM_PROT_EXECUTE)?"x":"-",
> "p",
> (u_long)off,
> 0,
> @@ -968,6 +974,16 @@ linprocfs_doprocmaps(PFS_FILL_ARGS)
> error = 0;
> break;
> }
> + vm_map_lock_read(map);
> + if (last_timestamp + 1 != map->timestamp) {
> + /*
> + * Look again for the entry because the map was
> + * modified while it was unlocked. Specifically,
> + * the entry may have been clipped, merged, or deleted.
> + */
> + vm_map_lookup_entry(map, e_end - 1, &tmp_entry);
> + entry = tmp_entry;
> + }
> }
> vm_map_unlock_read(map);
>
>
> Modified: head/sys/fs/procfs/procfs_map.c
> ==============================================================================
> --- head/sys/fs/procfs/procfs_map.c Mon Dec 8 12:29:30 2008
> (r185764)
> +++ head/sys/fs/procfs/procfs_map.c Mon Dec 8 12:34:52 2008
> (r185765)
> @@ -84,9 +84,10 @@ procfs_doprocmap(PFS_FILL_ARGS)
> {
> int error, vfslocked;
> vm_map_t map = &p->p_vmspace->vm_map;
> - vm_map_entry_t entry;
> + vm_map_entry_t entry, tmp_entry;
> struct vnode *vp;
> char *fullpath, *freepath;
> + unsigned int last_timestamp;
> #ifdef COMPAT_IA32
> int wrap32 = 0;
> #endif
> @@ -113,13 +114,19 @@ procfs_doprocmap(PFS_FILL_ARGS)
> entry = entry->next) {
> vm_object_t obj, tobj, lobj;
> int ref_count, shadow_count, flags;
> - vm_offset_t addr;
> + vm_offset_t e_start, e_end, addr;
> int resident, privateresident;
> char *type;
> + vm_eflags_t e_eflags;
> + vm_prot_t e_prot;
>
> if (entry->eflags & MAP_ENTRY_IS_SUB_MAP)
> continue;
>
> + e_eflags = entry->eflags;
> + e_prot = entry->protection;
> + e_start = entry->start;
> + e_end = entry->end;
> privateresident = 0;
> obj = entry->object.vm_object;
> if (obj != NULL) {
> @@ -143,11 +150,13 @@ procfs_doprocmap(PFS_FILL_ARGS)
> VM_OBJECT_UNLOCK(lobj);
> lobj = tobj;
> }
> + last_timestamp = map->timestamp;
> + vm_map_unlock_read(map);
>
> freepath = NULL;
> fullpath = "-";
> if (lobj) {
> - switch(lobj->type) {
> + switch (lobj->type) {
> default:
> case OBJT_DEFAULT:
> type = "default";
> @@ -193,19 +202,19 @@ procfs_doprocmap(PFS_FILL_ARGS)
> */
> error = sbuf_printf(sb,
> "0x%lx 0x%lx %d %d %p %s%s%s %d %d 0x%x %s %s %s %s\n",
> - (u_long)entry->start, (u_long)entry->end,
> + (u_long)e_start, (u_long)e_end,
> resident, privateresident,
> #ifdef COMPAT_IA32
> wrap32 ? NULL : obj, /* Hide 64 bit value */
> #else
> obj,
> #endif
> - (entry->protection & VM_PROT_READ)?"r":"-",
> - (entry->protection & VM_PROT_WRITE)?"w":"-",
> - (entry->protection & VM_PROT_EXECUTE)?"x":"-",
> + (e_prot & VM_PROT_READ)?"r":"-",
> + (e_prot & VM_PROT_WRITE)?"w":"-",
> + (e_prot & VM_PROT_EXECUTE)?"x":"-",
> ref_count, shadow_count, flags,
> - (entry->eflags & MAP_ENTRY_COW)?"COW":"NCOW",
> - (entry->eflags & MAP_ENTRY_NEEDS_COPY)?"NC":"NNC",
> + (e_eflags & MAP_ENTRY_COW)?"COW":"NCOW",
> + (e_eflags & MAP_ENTRY_NEEDS_COPY)?"NC":"NNC",
> type, fullpath);
>
> if (freepath != NULL)
> @@ -215,6 +224,16 @@ procfs_doprocmap(PFS_FILL_ARGS)
> error = 0;
> break;
> }
> + vm_map_lock_read(map);
> + if (last_timestamp + 1 != map->timestamp) {
> + /*
> + * Look again for the entry because the map was
> + * modified while it was unlocked. Specifically,
> + * the entry may have been clipped, merged, or deleted.
> + */
> + vm_map_lookup_entry(map, e_end - 1, &tmp_entry);
> + entry = tmp_entry;
> + }
> }
> vm_map_unlock_read(map);
> return (error);
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