| Message ID | 20240328140330.4747-1-urezki@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [1/1] mm: vmalloc: Fix lockdep warning | expand |
On 03/28/24 at 03:03pm, Uladzislau Rezki (Sony) wrote: > A lockdep reports a possible deadlock in the find_vmap_area_exceed_addr_lock() > function: > > ============================================ > WARNING: possible recursive locking detected > 6.9.0-rc1-00060-ged3ccc57b108-dirty #6140 Not tainted > -------------------------------------------- > drgn/455 is trying to acquire lock: > ffff0000c00131d0 (&vn->busy.lock/1){+.+.}-{2:2}, at: find_vmap_area_exceed_addr_lock+0x64/0x124 > > but task is already holding lock: > ffff0000c0011878 (&vn->busy.lock/1){+.+.}-{2:2}, at: find_vmap_area_exceed_addr_lock+0x64/0x124 > > other info that might help us debug this: > Possible unsafe locking scenario: > > CPU0 > ---- > lock(&vn->busy.lock/1); > lock(&vn->busy.lock/1); > > *** DEADLOCK *** > > indeed it can happen if the find_vmap_area_exceed_addr_lock() > gets called concurrently because it tries to acquire two nodes > locks. It was done to prevent removing a lowest VA found on a > previous step. > > To address this a lowest VA is found first without holding a > node lock where it resides. As a last step we check if a VA > still there because it can go away, if removed, proceed with > next lowest. > > Fixes: 53becf32aec1 ("mm: vmalloc: support multiple nodes in vread_iter") > Tested-by: Jens Axboe <axboe@kernel.dk> > Tested-by: Omar Sandoval <osandov@fb.com> > Reported-by: Jens Axboe <axboe@kernel.dk> > Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> > --- > mm/vmalloc.c | 74 +++++++++++++++++++++++++++++++--------------------- > 1 file changed, 44 insertions(+), 30 deletions(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index e94ce4562805..a5a5dfc3843e 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -989,6 +989,27 @@ unsigned long vmalloc_nr_pages(void) > return atomic_long_read(&nr_vmalloc_pages); > } > > +static struct vmap_area *__find_vmap_area(unsigned long addr, struct rb_root *root) > +{ > + struct rb_node *n = root->rb_node; > + > + addr = (unsigned long)kasan_reset_tag((void *)addr); > + > + while (n) { > + struct vmap_area *va; > + > + va = rb_entry(n, struct vmap_area, rb_node); > + if (addr < va->va_start) > + n = n->rb_left; > + else if (addr >= va->va_end) > + n = n->rb_right; > + else > + return va; > + } > + > + return NULL; > +} > + > /* Look up the first VA which satisfies addr < va_end, NULL if none. */ > static struct vmap_area * > __find_vmap_area_exceed_addr(unsigned long addr, struct rb_root *root) > @@ -1025,47 +1046,40 @@ __find_vmap_area_exceed_addr(unsigned long addr, struct rb_root *root) > static struct vmap_node * > find_vmap_area_exceed_addr_lock(unsigned long addr, struct vmap_area **va) > { > - struct vmap_node *vn, *va_node = NULL; > - struct vmap_area *va_lowest; > + unsigned long va_start_lowest; > + struct vmap_node *vn; > int i; > > - for (i = 0; i < nr_vmap_nodes; i++) { > +repeat: > + for (i = 0, va_start_lowest = 0; i < nr_vmap_nodes; i++) { > vn = &vmap_nodes[i]; > > spin_lock(&vn->busy.lock); > - va_lowest = __find_vmap_area_exceed_addr(addr, &vn->busy.root); > - if (va_lowest) { > - if (!va_node || va_lowest->va_start < (*va)->va_start) { > - if (va_node) > - spin_unlock(&va_node->busy.lock); > - > - *va = va_lowest; > - va_node = vn; > - continue; > - } > - } > + *va = __find_vmap_area_exceed_addr(addr, &vn->busy.root); > + > + if (*va) > + if (!va_start_lowest || (*va)->va_start < va_start_lowest) > + va_start_lowest = (*va)->va_start; How about below change about va_start_lowest? Personal preference, not strong opinion. diff --git a/mm/vmalloc.c b/mm/vmalloc.c index 9b1a41e12d70..bd6a66c54ad2 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -1046,19 +1046,19 @@ __find_vmap_area_exceed_addr(unsigned long addr, struct rb_root *root) static struct vmap_node * find_vmap_area_exceed_addr_lock(unsigned long addr, struct vmap_area **va) { - unsigned long va_start_lowest; + unsigned long va_start_lowest = ULONG_MAX; struct vmap_node *vn; int i; repeat: - for (i = 0, va_start_lowest = 0; i < nr_vmap_nodes; i++) { + for (i = 0; i < nr_vmap_nodes; i++) { vn = &vmap_nodes[i]; spin_lock(&vn->busy.lock); *va = __find_vmap_area_exceed_addr(addr, &vn->busy.root); if (*va) - if (!va_start_lowest || (*va)->va_start < va_start_lowest) + if ((*va)->va_start < va_start_lowest) va_start_lowest = (*va)->va_start; spin_unlock(&vn->busy.lock); } @@ -1069,7 +1069,7 @@ find_vmap_area_exceed_addr_lock(unsigned long addr, struct vmap_area **va) * been removed concurrently thus we need to proceed * with next one what is a rare case. */ - if (va_start_lowest) { + if (va_start_lowest != ULONG_MAX) { vn = addr_to_node(va_start_lowest); spin_lock(&vn->busy.lock); > spin_unlock(&vn->busy.lock); > } > > - return va_node; > -} > - > -static struct vmap_area *__find_vmap_area(unsigned long addr, struct rb_root *root) > -{ > - struct rb_node *n = root->rb_node; > + /* > + * Check if found VA exists, it might it is gone away. ~~~~ grammer mistake? > + * In this case we repeat the search because a VA has > + * been removed concurrently thus we need to proceed > + * with next one what is a rare case. ~~~~ typo, which? > + */ > + if (va_start_lowest) { > + vn = addr_to_node(va_start_lowest); > > - addr = (unsigned long)kasan_reset_tag((void *)addr); > + spin_lock(&vn->busy.lock); > + *va = __find_vmap_area(va_start_lowest, &vn->busy.root); > > - while (n) { > - struct vmap_area *va; > + if (*va) > + return vn; > > - va = rb_entry(n, struct vmap_area, rb_node); > - if (addr < va->va_start) > - n = n->rb_left; > - else if (addr >= va->va_end) > - n = n->rb_right; > - else > - return va; > + spin_unlock(&vn->busy.lock); > + goto repeat; > } Other than above nickpick concerns, this looks good to me. Reviewed-by: Baoquan He <bhe@redhat.com>
On Fri, Mar 29, 2024 at 03:44:40PM +0800, Baoquan He wrote: > On 03/28/24 at 03:03pm, Uladzislau Rezki (Sony) wrote: > > A lockdep reports a possible deadlock in the find_vmap_area_exceed_addr_lock() > > function: > > > > ============================================ > > WARNING: possible recursive locking detected > > 6.9.0-rc1-00060-ged3ccc57b108-dirty #6140 Not tainted > > -------------------------------------------- > > drgn/455 is trying to acquire lock: > > ffff0000c00131d0 (&vn->busy.lock/1){+.+.}-{2:2}, at: find_vmap_area_exceed_addr_lock+0x64/0x124 > > > > but task is already holding lock: > > ffff0000c0011878 (&vn->busy.lock/1){+.+.}-{2:2}, at: find_vmap_area_exceed_addr_lock+0x64/0x124 > > > > other info that might help us debug this: > > Possible unsafe locking scenario: > > > > CPU0 > > ---- > > lock(&vn->busy.lock/1); > > lock(&vn->busy.lock/1); > > > > *** DEADLOCK *** > > > > indeed it can happen if the find_vmap_area_exceed_addr_lock() > > gets called concurrently because it tries to acquire two nodes > > locks. It was done to prevent removing a lowest VA found on a > > previous step. > > > > To address this a lowest VA is found first without holding a > > node lock where it resides. As a last step we check if a VA > > still there because it can go away, if removed, proceed with > > next lowest. > > > > Fixes: 53becf32aec1 ("mm: vmalloc: support multiple nodes in vread_iter") > > Tested-by: Jens Axboe <axboe@kernel.dk> > > Tested-by: Omar Sandoval <osandov@fb.com> > > Reported-by: Jens Axboe <axboe@kernel.dk> > > Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> > > --- > > mm/vmalloc.c | 74 +++++++++++++++++++++++++++++++--------------------- > > 1 file changed, 44 insertions(+), 30 deletions(-) > > > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > > index e94ce4562805..a5a5dfc3843e 100644 > > --- a/mm/vmalloc.c > > +++ b/mm/vmalloc.c > > @@ -989,6 +989,27 @@ unsigned long vmalloc_nr_pages(void) > > return atomic_long_read(&nr_vmalloc_pages); > > } > > > > +static struct vmap_area *__find_vmap_area(unsigned long addr, struct rb_root *root) > > +{ > > + struct rb_node *n = root->rb_node; > > + > > + addr = (unsigned long)kasan_reset_tag((void *)addr); > > + > > + while (n) { > > + struct vmap_area *va; > > + > > + va = rb_entry(n, struct vmap_area, rb_node); > > + if (addr < va->va_start) > > + n = n->rb_left; > > + else if (addr >= va->va_end) > > + n = n->rb_right; > > + else > > + return va; > > + } > > + > > + return NULL; > > +} > > + > > /* Look up the first VA which satisfies addr < va_end, NULL if none. */ > > static struct vmap_area * > > __find_vmap_area_exceed_addr(unsigned long addr, struct rb_root *root) > > @@ -1025,47 +1046,40 @@ __find_vmap_area_exceed_addr(unsigned long addr, struct rb_root *root) > > static struct vmap_node * > > find_vmap_area_exceed_addr_lock(unsigned long addr, struct vmap_area **va) > > { > > - struct vmap_node *vn, *va_node = NULL; > > - struct vmap_area *va_lowest; > > + unsigned long va_start_lowest; > > + struct vmap_node *vn; > > int i; > > > > - for (i = 0; i < nr_vmap_nodes; i++) { > > +repeat: > > + for (i = 0, va_start_lowest = 0; i < nr_vmap_nodes; i++) { > > vn = &vmap_nodes[i]; > > > > spin_lock(&vn->busy.lock); > > - va_lowest = __find_vmap_area_exceed_addr(addr, &vn->busy.root); > > - if (va_lowest) { > > - if (!va_node || va_lowest->va_start < (*va)->va_start) { > > - if (va_node) > > - spin_unlock(&va_node->busy.lock); > > - > > - *va = va_lowest; > > - va_node = vn; > > - continue; > > - } > > - } > > + *va = __find_vmap_area_exceed_addr(addr, &vn->busy.root); > > + > > + if (*va) > > + if (!va_start_lowest || (*va)->va_start < va_start_lowest) > > + va_start_lowest = (*va)->va_start; > > How about below change about va_start_lowest? Personal preference, not > strong opinion. > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 9b1a41e12d70..bd6a66c54ad2 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -1046,19 +1046,19 @@ __find_vmap_area_exceed_addr(unsigned long addr, struct rb_root *root) > static struct vmap_node * > find_vmap_area_exceed_addr_lock(unsigned long addr, struct vmap_area **va) > { > - unsigned long va_start_lowest; > + unsigned long va_start_lowest = ULONG_MAX; > struct vmap_node *vn; > int i; > > repeat: > - for (i = 0, va_start_lowest = 0; i < nr_vmap_nodes; i++) { > + for (i = 0; i < nr_vmap_nodes; i++) { > vn = &vmap_nodes[i]; > > spin_lock(&vn->busy.lock); > *va = __find_vmap_area_exceed_addr(addr, &vn->busy.root); > > if (*va) > - if (!va_start_lowest || (*va)->va_start < va_start_lowest) > + if ((*va)->va_start < va_start_lowest) > va_start_lowest = (*va)->va_start; > spin_unlock(&vn->busy.lock); > } > @@ -1069,7 +1069,7 @@ find_vmap_area_exceed_addr_lock(unsigned long addr, struct vmap_area **va) > * been removed concurrently thus we need to proceed > * with next one what is a rare case. > */ > - if (va_start_lowest) { > + if (va_start_lowest != ULONG_MAX) { > vn = addr_to_node(va_start_lowest); > > spin_lock(&vn->busy.lock); > > To me it looks as incomplete. The "va_start_lowest" should be initialized when repeat. Otherwise we can end up with an infinite repeating because va_start_lowest != ULONG_MAX. > > } > > > > - return va_node; > > -} > > - > > -static struct vmap_area *__find_vmap_area(unsigned long addr, struct rb_root *root) > > -{ > > - struct rb_node *n = root->rb_node; > > + /* > > + * Check if found VA exists, it might it is gone away. > ~~~~ grammer mistake? > > + * In this case we repeat the search because a VA has > > + * been removed concurrently thus we need to proceed > > + * with next one what is a rare case. > ~~~~ typo, which? > > + */ > > + if (va_start_lowest) { > > + vn = addr_to_node(va_start_lowest); > > > > - addr = (unsigned long)kasan_reset_tag((void *)addr); > > + spin_lock(&vn->busy.lock); > > + *va = __find_vmap_area(va_start_lowest, &vn->busy.root); > > > > - while (n) { > > - struct vmap_area *va; > > + if (*va) > > + return vn; > > > > - va = rb_entry(n, struct vmap_area, rb_node); > > - if (addr < va->va_start) > > - n = n->rb_left; > > - else if (addr >= va->va_end) > > - n = n->rb_right; > > - else > > - return va; > > + spin_unlock(&vn->busy.lock); > > + goto repeat; > > } > > Other than above nickpick concerns, this looks good to me. > > Reviewed-by: Baoquan He <bhe@redhat.com> > Thank you! -- Uladzislau Rezki
On 03/30/24 at 01:55pm, Uladzislau Rezki wrote: > On Fri, Mar 29, 2024 at 03:44:40PM +0800, Baoquan He wrote: > > On 03/28/24 at 03:03pm, Uladzislau Rezki (Sony) wrote: ......snip > > How about below change about va_start_lowest? Personal preference, not > > strong opinion. > > > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > > index 9b1a41e12d70..bd6a66c54ad2 100644 > > --- a/mm/vmalloc.c > > +++ b/mm/vmalloc.c > > @@ -1046,19 +1046,19 @@ __find_vmap_area_exceed_addr(unsigned long addr, struct rb_root *root) > > static struct vmap_node * > > find_vmap_area_exceed_addr_lock(unsigned long addr, struct vmap_area **va) > > { > > - unsigned long va_start_lowest; > > + unsigned long va_start_lowest = ULONG_MAX; > > struct vmap_node *vn; > > int i; > > > > repeat: > > - for (i = 0, va_start_lowest = 0; i < nr_vmap_nodes; i++) { > > + for (i = 0; i < nr_vmap_nodes; i++) { > > vn = &vmap_nodes[i]; > > > > spin_lock(&vn->busy.lock); > > *va = __find_vmap_area_exceed_addr(addr, &vn->busy.root); > > > > if (*va) > > - if (!va_start_lowest || (*va)->va_start < va_start_lowest) > > + if ((*va)->va_start < va_start_lowest) > > va_start_lowest = (*va)->va_start; > > spin_unlock(&vn->busy.lock); > > } > > @@ -1069,7 +1069,7 @@ find_vmap_area_exceed_addr_lock(unsigned long addr, struct vmap_area **va) > > * been removed concurrently thus we need to proceed > > * with next one what is a rare case. > > */ > > - if (va_start_lowest) { > > + if (va_start_lowest != ULONG_MAX) { > > vn = addr_to_node(va_start_lowest); > > > > spin_lock(&vn->busy.lock); > > > > > To me it looks as incomplete. The "va_start_lowest" should be initialized > when repeat. Otherwise we can end up with an infinite repeating because > va_start_lowest != ULONG_MAX. You are right. Anyway, it's just a suggestion from a different code style, please feel free to adjust it in or leave the patch as is. > > > > } > > > > > > - return va_node; > > > -} > > > - > > > -static struct vmap_area *__find_vmap_area(unsigned long addr, struct rb_root *root) > > > -{ > > > - struct rb_node *n = root->rb_node; > > > + /* > > > + * Check if found VA exists, it might it is gone away. > > ~~~~ grammer mistake? > > > + * In this case we repeat the search because a VA has > > > + * been removed concurrently thus we need to proceed > > > + * with next one what is a rare case. > > ~~~~ typo, which? > > > + */ > > > + if (va_start_lowest) { > > > + vn = addr_to_node(va_start_lowest); > > > > > > - addr = (unsigned long)kasan_reset_tag((void *)addr); > > > + spin_lock(&vn->busy.lock); > > > + *va = __find_vmap_area(va_start_lowest, &vn->busy.root); > > > > > > - while (n) { > > > - struct vmap_area *va; > > > + if (*va) > > > + return vn; > > > > > > - va = rb_entry(n, struct vmap_area, rb_node); > > > - if (addr < va->va_start) > > > - n = n->rb_left; > > > - else if (addr >= va->va_end) > > > - n = n->rb_right; > > > - else > > > - return va; > > > + spin_unlock(&vn->busy.lock); > > > + goto repeat; > > > } > > > > Other than above nickpick concerns, this looks good to me. > > > > Reviewed-by: Baoquan He <bhe@redhat.com> > > > Thank you! > > -- > Uladzislau Rezki >
On Sat, Mar 30, 2024 at 09:21:25PM +0800, Baoquan He wrote: > On 03/30/24 at 01:55pm, Uladzislau Rezki wrote: > > On Fri, Mar 29, 2024 at 03:44:40PM +0800, Baoquan He wrote: > > > On 03/28/24 at 03:03pm, Uladzislau Rezki (Sony) wrote: > ......snip > > > How about below change about va_start_lowest? Personal preference, not > > > strong opinion. > > > > > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > > > index 9b1a41e12d70..bd6a66c54ad2 100644 > > > --- a/mm/vmalloc.c > > > +++ b/mm/vmalloc.c > > > @@ -1046,19 +1046,19 @@ __find_vmap_area_exceed_addr(unsigned long addr, struct rb_root *root) > > > static struct vmap_node * > > > find_vmap_area_exceed_addr_lock(unsigned long addr, struct vmap_area **va) > > > { > > > - unsigned long va_start_lowest; > > > + unsigned long va_start_lowest = ULONG_MAX; > > > struct vmap_node *vn; > > > int i; > > > > > > repeat: > > > - for (i = 0, va_start_lowest = 0; i < nr_vmap_nodes; i++) { > > > + for (i = 0; i < nr_vmap_nodes; i++) { > > > vn = &vmap_nodes[i]; > > > > > > spin_lock(&vn->busy.lock); > > > *va = __find_vmap_area_exceed_addr(addr, &vn->busy.root); > > > > > > if (*va) > > > - if (!va_start_lowest || (*va)->va_start < va_start_lowest) > > > + if ((*va)->va_start < va_start_lowest) > > > va_start_lowest = (*va)->va_start; > > > spin_unlock(&vn->busy.lock); > > > } > > > @@ -1069,7 +1069,7 @@ find_vmap_area_exceed_addr_lock(unsigned long addr, struct vmap_area **va) > > > * been removed concurrently thus we need to proceed > > > * with next one what is a rare case. > > > */ > > > - if (va_start_lowest) { > > > + if (va_start_lowest != ULONG_MAX) { > > > vn = addr_to_node(va_start_lowest); > > > > > > spin_lock(&vn->busy.lock); > > > > > > > > To me it looks as incomplete. The "va_start_lowest" should be initialized > > when repeat. Otherwise we can end up with an infinite repeating because > > va_start_lowest != ULONG_MAX. > > You are right. Anyway, it's just a suggestion from a different code > style, please feel free to adjust it in or leave the patch as is. > > > OK! Thank you. -- Uladzislau Rezki
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index e94ce4562805..a5a5dfc3843e 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -989,6 +989,27 @@ unsigned long vmalloc_nr_pages(void) return atomic_long_read(&nr_vmalloc_pages); } +static struct vmap_area *__find_vmap_area(unsigned long addr, struct rb_root *root) +{ + struct rb_node *n = root->rb_node; + + addr = (unsigned long)kasan_reset_tag((void *)addr); + + while (n) { + struct vmap_area *va; + + va = rb_entry(n, struct vmap_area, rb_node); + if (addr < va->va_start) + n = n->rb_left; + else if (addr >= va->va_end) + n = n->rb_right; + else + return va; + } + + return NULL; +} + /* Look up the first VA which satisfies addr < va_end, NULL if none. */ static struct vmap_area * __find_vmap_area_exceed_addr(unsigned long addr, struct rb_root *root) @@ -1025,47 +1046,40 @@ __find_vmap_area_exceed_addr(unsigned long addr, struct rb_root *root) static struct vmap_node * find_vmap_area_exceed_addr_lock(unsigned long addr, struct vmap_area **va) { - struct vmap_node *vn, *va_node = NULL; - struct vmap_area *va_lowest; + unsigned long va_start_lowest; + struct vmap_node *vn; int i; - for (i = 0; i < nr_vmap_nodes; i++) { +repeat: + for (i = 0, va_start_lowest = 0; i < nr_vmap_nodes; i++) { vn = &vmap_nodes[i]; spin_lock(&vn->busy.lock); - va_lowest = __find_vmap_area_exceed_addr(addr, &vn->busy.root); - if (va_lowest) { - if (!va_node || va_lowest->va_start < (*va)->va_start) { - if (va_node) - spin_unlock(&va_node->busy.lock); - - *va = va_lowest; - va_node = vn; - continue; - } - } + *va = __find_vmap_area_exceed_addr(addr, &vn->busy.root); + + if (*va) + if (!va_start_lowest || (*va)->va_start < va_start_lowest) + va_start_lowest = (*va)->va_start; spin_unlock(&vn->busy.lock); } - return va_node; -} - -static struct vmap_area *__find_vmap_area(unsigned long addr, struct rb_root *root) -{ - struct rb_node *n = root->rb_node; + /* + * Check if found VA exists, it might it is gone away. + * In this case we repeat the search because a VA has + * been removed concurrently thus we need to proceed + * with next one what is a rare case. + */ + if (va_start_lowest) { + vn = addr_to_node(va_start_lowest); - addr = (unsigned long)kasan_reset_tag((void *)addr); + spin_lock(&vn->busy.lock); + *va = __find_vmap_area(va_start_lowest, &vn->busy.root); - while (n) { - struct vmap_area *va; + if (*va) + return vn; - va = rb_entry(n, struct vmap_area, rb_node); - if (addr < va->va_start) - n = n->rb_left; - else if (addr >= va->va_end) - n = n->rb_right; - else - return va; + spin_unlock(&vn->busy.lock); + goto repeat; } return NULL;
A lockdep reports a possible deadlock in the find_vmap_area_exceed_addr_lock() function: ============================================ WARNING: possible recursive locking detected 6.9.0-rc1-00060-ged3ccc57b108-dirty #6140 Not tainted -------------------------------------------- drgn/455 is trying to acquire lock: ffff0000c00131d0 (&vn->busy.lock/1){+.+.}-{2:2}, at: find_vmap_area_exceed_addr_lock+0x64/0x124 but task is already holding lock: ffff0000c0011878 (&vn->busy.lock/1){+.+.}-{2:2}, at: find_vmap_area_exceed_addr_lock+0x64/0x124 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&vn->busy.lock/1); lock(&vn->busy.lock/1); *** DEADLOCK *** indeed it can happen if the find_vmap_area_exceed_addr_lock() gets called concurrently because it tries to acquire two nodes locks. It was done to prevent removing a lowest VA found on a previous step. To address this a lowest VA is found first without holding a node lock where it resides. As a last step we check if a VA still there because it can go away, if removed, proceed with next lowest. Fixes: 53becf32aec1 ("mm: vmalloc: support multiple nodes in vread_iter") Tested-by: Jens Axboe <axboe@kernel.dk> Tested-by: Omar Sandoval <osandov@fb.com> Reported-by: Jens Axboe <axboe@kernel.dk> Signed-off-by: Uladzislau Rezki (Sony) <urezki@gmail.com> --- mm/vmalloc.c | 74 +++++++++++++++++++++++++++++++--------------------- 1 file changed, 44 insertions(+), 30 deletions(-)