diff mbox series

[net,v2] igb: cope with large MAX_SKB_FRAGS

Message ID 20240816152034.1453285-1-vinschen@redhat.com (mailing list archive)
State Accepted
Commit 8aba27c4a5020abdf60149239198297f88338a8d
Delegated to: Netdev Maintainers
Headers show
Series [net,v2] igb: cope with large MAX_SKB_FRAGS | expand

Checks

Context Check Description
netdev/series_format success Single patches do not need cover letters
netdev/tree_selection success Clearly marked for net
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag present in non-next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 16 this patch: 16
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers fail 2 blamed authors not CCed: kerneljasonxing@gmail.com razor@blackwall.org; 4 maintainers not CCed: przemyslaw.kitszel@intel.com razor@blackwall.org intel-wired-lan@lists.osuosl.org kerneljasonxing@gmail.com
netdev/build_clang success Errors and warnings before: 16 this patch: 16
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 16 this patch: 16
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 7 lines checked
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 38 this patch: 38
netdev/source_inline success Was 0 now: 0
netdev/contest success net-next-2024-08-20--09-00 (tests: 712)

Commit Message

Corinna Vinschen Aug. 16, 2024, 3:20 p.m. UTC 
From: Paolo Abeni <pabeni@redhat.com>

Sabrina reports that the igb driver does not cope well with large
MAX_SKB_FRAG values: setting MAX_SKB_FRAG to 45 causes payload
corruption on TX.

An easy reproducer is to run ssh to connect to the machine.  With
MAX_SKB_FRAGS=17 it works, with MAX_SKB_FRAGS=45 it fails.  This has
been reported originally in
https://bugzilla.redhat.com/show_bug.cgi?id=2265320

The root cause of the issue is that the driver does not take into
account properly the (possibly large) shared info size when selecting
the ring layout, and will try to fit two packets inside the same 4K
page even when the 1st fraglist will trump over the 2nd head.

Address the issue by checking if 2K buffers are insufficient.

Fixes: 3948b05950fd ("net: introduce a config option to tweak MAX_SKB_FRAGS")
Reported-by: Jan Tluka <jtluka@redhat.com>
Reported-by: Jirka Hladky <jhladky@redhat.com>
Reported-by: Sabrina Dubroca <sd@queasysnail.net>
Tested-by: Sabrina Dubroca <sd@queasysnail.net>
Tested-by: Corinna Vinschen <vinschen@redhat.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Corinna Vinschen <vinschen@redhat.com>
---
 drivers/net/ethernet/intel/igb/igb_main.c | 1 +
 1 file changed, 1 insertion(+)

v2: utilize IGB_2K_TOO_SMALL_WITH_PADDING

Comments

patchwork-bot+netdevbpf@kernel.org Aug. 20, 2024, 10:50 p.m. UTC | #1 
Hello:

This patch was applied to netdev/net.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Fri, 16 Aug 2024 17:20:34 +0200 you wrote:
> From: Paolo Abeni <pabeni@redhat.com>
> 
> Sabrina reports that the igb driver does not cope well with large
> MAX_SKB_FRAG values: setting MAX_SKB_FRAG to 45 causes payload
> corruption on TX.
> 
> An easy reproducer is to run ssh to connect to the machine.  With
> MAX_SKB_FRAGS=17 it works, with MAX_SKB_FRAGS=45 it fails.  This has
> been reported originally in
> https://bugzilla.redhat.com/show_bug.cgi?id=2265320
> 
> [...]

Here is the summary with links:
  - [net,v2] igb: cope with large MAX_SKB_FRAGS
    https://git.kernel.org/netdev/net/c/8aba27c4a502

You are awesome, thank you!
Fijalkowski, Maciej Aug. 21, 2024, 6:23 a.m. UTC | #2 
> 
> Hello:
> 
> This patch was applied to netdev/net.git (main)
> by Jakub Kicinski <kuba@kernel.org>:
> 
> On Fri, 16 Aug 2024 17:20:34 +0200 you wrote:
> > From: Paolo Abeni <pabeni@redhat.com>
> >
> > Sabrina reports that the igb driver does not cope well with large
> > MAX_SKB_FRAG values: setting MAX_SKB_FRAG to 45 causes payload
> > corruption on TX.
> >
> > An easy reproducer is to run ssh to connect to the machine.  With
> > MAX_SKB_FRAGS=17 it works, with MAX_SKB_FRAGS=45 it fails.  This has
> > been reported originally in
> > https://bugzilla.redhat.com/show_bug.cgi?id=2265320

Eh, I missed giving my reviewed-by tag. FWIW thanks for this v2!

> >
> > [...]
> 
> Here is the summary with links:
>   - [net,v2] igb: cope with large MAX_SKB_FRAGS
>     https://git.kernel.org/netdev/net/c/8aba27c4a502
> 
> You are awesome, thank you!
> --
> Deet-doot-dot, I am a bot.
> https://korg.docs.kernel.org/patchwork/pwbot.html
>
diff mbox series

Patch

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 11be39f435f3..33a42b4c21e0 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -4808,6 +4808,7 @@  static void igb_set_rx_buffer_len(struct igb_adapter *adapter,
 
 #if (PAGE_SIZE < 8192)
 	if (adapter->max_frame_size > IGB_MAX_FRAME_BUILD_SKB ||
+	    IGB_2K_TOO_SMALL_WITH_PADDING ||
 	    rd32(E1000_RCTL) & E1000_RCTL_SBP)
 		set_ring_uses_large_buffer(rx_ring);
 #endif