[next] mtd: maps: physmap: Fix infinite loop crash in ROM type probing
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Message ID 20181106214416.11342-1-geert@linux-m68k.org
State New, archived
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  • [next] mtd: maps: physmap: Fix infinite loop crash in ROM type probing
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Commit Message

Geert Uytterhoeven Nov. 6, 2018, 9:44 p.m. UTC
On Toshiba RBTX4927, where map_probe is supposed to fail:

    Creating 2 MTD partitions on "physmap-flash.0":
    0x000000c00000-0x000001000000 : "boot"
    0x000000000000-0x000000c00000 : "user"
    physmap-flash physmap-flash.1: physmap platform flash device: [mem 0x1e000000-0x1effffff]
    CPU 0 Unable to handle kernel paging request at virtual address 00000000, epc == 80320f40, ra == 80321004
    ...
    Call Trace:
    [<80320f40>] get_mtd_chip_driver+0x30/0x8c
    [<80321004>] do_map_probe+0x20/0x90
    [<80328448>] physmap_flash_probe+0x484/0x4ec

The access to rom_probe_types[] was changed from a sentinel-based loop
to an infinite loop, causing a crash when reaching the sentinel.

Fix this by:
  - Removing the no longer needed sentinel,
  - Limiting the number of loop iterations to the actual number of ROM
    types.

Fixes: c7afe08496fa463e ("mtd: maps: physmap: Invert logic on if/else branch")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
---
 drivers/mtd/maps/physmap-core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Comments

Boris Brezillon Nov. 6, 2018, 9:58 p.m. UTC | #1
On Tue,  6 Nov 2018 22:44:16 +0100
Geert Uytterhoeven <geert@linux-m68k.org> wrote:

> On Toshiba RBTX4927, where map_probe is supposed to fail:
> 
>     Creating 2 MTD partitions on "physmap-flash.0":
>     0x000000c00000-0x000001000000 : "boot"
>     0x000000000000-0x000000c00000 : "user"
>     physmap-flash physmap-flash.1: physmap platform flash device: [mem 0x1e000000-0x1effffff]
>     CPU 0 Unable to handle kernel paging request at virtual address 00000000, epc == 80320f40, ra == 80321004
>     ...
>     Call Trace:
>     [<80320f40>] get_mtd_chip_driver+0x30/0x8c
>     [<80321004>] do_map_probe+0x20/0x90
>     [<80328448>] physmap_flash_probe+0x484/0x4ec
> 
> The access to rom_probe_types[] was changed from a sentinel-based loop
> to an infinite loop, causing a crash when reaching the sentinel.

Oops. Do you mind if I fix that in-place (squash your changes in
Ricardo's original commit)?

> 
> Fix this by:
>   - Removing the no longer needed sentinel,
>   - Limiting the number of loop iterations to the actual number of ROM
>     types.
> 
> Fixes: c7afe08496fa463e ("mtd: maps: physmap: Invert logic on if/else branch")
> Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
> ---
>  drivers/mtd/maps/physmap-core.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/mtd/maps/physmap-core.c b/drivers/mtd/maps/physmap-core.c
> index 33b77bd9022ce251..e8c3b250d8421edc 100644
> --- a/drivers/mtd/maps/physmap-core.c
> +++ b/drivers/mtd/maps/physmap-core.c
> @@ -396,7 +396,7 @@ static int physmap_flash_of_init(struct platform_device *dev)
>  #endif /* IS_ENABLED(CONFIG_MTD_PHYSMAP_OF) */
>  
>  static const char * const rom_probe_types[] = {
> -	"cfi_probe", "jedec_probe", "qinfo_probe", "map_rom", NULL
> +	"cfi_probe", "jedec_probe", "qinfo_probe", "map_rom",
>  };
>  
>  static const char * const part_probe_types[] = {
> @@ -524,7 +524,7 @@ static int physmap_flash_probe(struct platform_device *dev)
>  		} else {
>  			int j;
>  
> -			for (j = 0; ARRAY_SIZE(rom_probe_types); j++) {
> +			for (j = 0; j < ARRAY_SIZE(rom_probe_types); j++) {
>  				info->mtds[i] = do_map_probe(rom_probe_types[j],
>  							     &info->maps[i]);
>  				if (info->mtds[i])
Geert Uytterhoeven Nov. 6, 2018, 10:19 p.m. UTC | #2
Hi Boris,

On Tue, Nov 6, 2018 at 10:58 PM Boris Brezillon
<boris.brezillon@bootlin.com> wrote:
> On Tue,  6 Nov 2018 22:44:16 +0100
> Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > On Toshiba RBTX4927, where map_probe is supposed to fail:
> >
> >     Creating 2 MTD partitions on "physmap-flash.0":
> >     0x000000c00000-0x000001000000 : "boot"
> >     0x000000000000-0x000000c00000 : "user"
> >     physmap-flash physmap-flash.1: physmap platform flash device: [mem 0x1e000000-0x1effffff]
> >     CPU 0 Unable to handle kernel paging request at virtual address 00000000, epc == 80320f40, ra == 80321004
> >     ...
> >     Call Trace:
> >     [<80320f40>] get_mtd_chip_driver+0x30/0x8c
> >     [<80321004>] do_map_probe+0x20/0x90
> >     [<80328448>] physmap_flash_probe+0x484/0x4ec
> >
> > The access to rom_probe_types[] was changed from a sentinel-based loop
> > to an infinite loop, causing a crash when reaching the sentinel.
>
> Oops. Do you mind if I fix that in-place (squash your changes in
> Ricardo's original commit)?

No problem. Thanks!

Gr{oetje,eeting}s,

                        Geert
Boris Brezillon Nov. 6, 2018, 10:34 p.m. UTC | #3
On Tue, 6 Nov 2018 23:19:14 +0100
Geert Uytterhoeven <geert@linux-m68k.org> wrote:

> Hi Boris,
> 
> On Tue, Nov 6, 2018 at 10:58 PM Boris Brezillon
> <boris.brezillon@bootlin.com> wrote:
> > On Tue,  6 Nov 2018 22:44:16 +0100
> > Geert Uytterhoeven <geert@linux-m68k.org> wrote:  
> > > On Toshiba RBTX4927, where map_probe is supposed to fail:
> > >
> > >     Creating 2 MTD partitions on "physmap-flash.0":
> > >     0x000000c00000-0x000001000000 : "boot"
> > >     0x000000000000-0x000000c00000 : "user"
> > >     physmap-flash physmap-flash.1: physmap platform flash device: [mem 0x1e000000-0x1effffff]
> > >     CPU 0 Unable to handle kernel paging request at virtual address 00000000, epc == 80320f40, ra == 80321004
> > >     ...
> > >     Call Trace:
> > >     [<80320f40>] get_mtd_chip_driver+0x30/0x8c
> > >     [<80321004>] do_map_probe+0x20/0x90
> > >     [<80328448>] physmap_flash_probe+0x484/0x4ec
> > >
> > > The access to rom_probe_types[] was changed from a sentinel-based loop
> > > to an infinite loop, causing a crash when reaching the sentinel.  
> >
> > Oops. Do you mind if I fix that in-place (squash your changes in
> > Ricardo's original commit)?

Done.

> 
> No problem. Thanks!

Thanks for reporting/fixing the bug.

Boris
Ricardo Ribalda Delgado Nov. 7, 2018, 7:33 a.m. UTC | #4
Hi Boris and Geert

On Tue, Nov 6, 2018 at 11:34 PM Boris Brezillon
<boris.brezillon@bootlin.com> wrote:
>
> On Tue, 6 Nov 2018 23:19:14 +0100
> Geert Uytterhoeven <geert@linux-m68k.org> wrote:
>
> > Hi Boris,
> >
> > On Tue, Nov 6, 2018 at 10:58 PM Boris Brezillon
> > <boris.brezillon@bootlin.com> wrote:
> > > On Tue,  6 Nov 2018 22:44:16 +0100
> > > Geert Uytterhoeven <geert@linux-m68k.org> wrote:
> > > > On Toshiba RBTX4927, where map_probe is supposed to fail:
> > > >
> > > >     Creating 2 MTD partitions on "physmap-flash.0":
> > > >     0x000000c00000-0x000001000000 : "boot"
> > > >     0x000000000000-0x000000c00000 : "user"
> > > >     physmap-flash physmap-flash.1: physmap platform flash device: [mem 0x1e000000-0x1effffff]
> > > >     CPU 0 Unable to handle kernel paging request at virtual address 00000000, epc == 80320f40, ra == 80321004
> > > >     ...
> > > >     Call Trace:
> > > >     [<80320f40>] get_mtd_chip_driver+0x30/0x8c
> > > >     [<80321004>] do_map_probe+0x20/0x90
> > > >     [<80328448>] physmap_flash_probe+0x484/0x4ec
> > > >
> > > > The access to rom_probe_types[] was changed from a sentinel-based loop
> > > > to an infinite loop, causing a crash when reaching the sentinel.
> > >
> > > Oops. Do you mind if I fix that in-place (squash your changes in
> > > Ricardo's original commit)?
>
> Done.
>
> >
> > No problem. Thanks!
>

Thanks to both of you for fixing this .
> Thanks for reporting/fixing the bug.
>
> Boris
>

Patch
diff mbox series

diff --git a/drivers/mtd/maps/physmap-core.c b/drivers/mtd/maps/physmap-core.c
index 33b77bd9022ce251..e8c3b250d8421edc 100644
--- a/drivers/mtd/maps/physmap-core.c
+++ b/drivers/mtd/maps/physmap-core.c
@@ -396,7 +396,7 @@  static int physmap_flash_of_init(struct platform_device *dev)
 #endif /* IS_ENABLED(CONFIG_MTD_PHYSMAP_OF) */
 
 static const char * const rom_probe_types[] = {
-	"cfi_probe", "jedec_probe", "qinfo_probe", "map_rom", NULL
+	"cfi_probe", "jedec_probe", "qinfo_probe", "map_rom",
 };
 
 static const char * const part_probe_types[] = {
@@ -524,7 +524,7 @@  static int physmap_flash_probe(struct platform_device *dev)
 		} else {
 			int j;
 
-			for (j = 0; ARRAY_SIZE(rom_probe_types); j++) {
+			for (j = 0; j < ARRAY_SIZE(rom_probe_types); j++) {
 				info->mtds[i] = do_map_probe(rom_probe_types[j],
 							     &info->maps[i]);
 				if (info->mtds[i])